Anatomy Exam 1 - Part 3
Teres Major
Teres major lies just inferior to teres minor and inserts medial to latissimus dorsi. P: inferior angle of scapula D: medial lip/crest of intertubercular sulcus
The median n. supplies the thenar muscles via a _______ _______.
The median n. supplies the thenar muscles via a recurrent branch.
Radial Nerve Injury (the most common radial nerve injury is what?)
The most common mechanism for radial n. injury is via a fracture of the humeral shaft. This injury is distal to the branches that innervate the triceps and skin on the posterior arm, but proximal to branches that supply the forearm and hand.
Carpal Tunnel
The palmar surface of the wrist is concave secondary to the position of the carpal bones. Together, the carpal bones form a carpal arch which participates in forming the carpal tunnel.
Posterior Interosseous N.
The posterior interosseus nerve innervates the remaining forearm extensors. The posterior interosseus n. travels along the posterior surface of the intersosseus membrane.
The ulnar artery exits the forearm with the ulnar nerve via___________
The ulnar artery exits the forearm with the ulnar nerve via the ulnar tunnel.
Radial and Ulnar artery continuation
The ulnar artery itself continues down the anterior forearm deep to FCU. The radial artery continues down the anterior forearm deep to brachioradialis.
Thenar Compartment "OAF" Abductor pollicis brevis
Thenar Compartment "OAF" Abductor pollicis brevis P: scaphoid and trapezium D: proximal phalanx
Thenar Compartment "OAF" Opponens Pollicis:
Thenar Compartment "OAF" Opponens Pollicis: P: trapezium D:1st metacarpal laterally
Together, the fibrous digital sheaths and underlying bone form________
Together, the fibrous digital sheaths and underlying bone form osseofibrous tunnels.
What makes up the "triangular interval"
Triangular interval (triceps hiatus) defined by the long head of triceps, teres major and the humerus. The triangular interval transmits the radial n. and the profunda (deep) brachial a. as they begin their course around the spiral groove.
What makes up the "triangular space"
Triangular space is defined by the teres minor, teres major and long head of the triceps. This space transmits the circumflex scapular a. Scapular and spinoglenoid notches transmit the suprascapular a. and n. Medial border of the scapula transmits the dorsal scapular a. and n.
Triceps
Triceps #1- 3 P: Long head - infraglenoid tubercle #1 Medial head-posterior humerus inferior to radial groove #2 Lateral head-posterior humerus superior to radial groove #3 D: Olecranon process of ulna
Ulnar collateral ligament
Ulnar collateral ligament is triangular in shape with an anterior cordlike part, a posterior fan-like part both arising from the medial epicondyle as well as a small oblique part arising from the olecranon.
Which is greater ulnar deviation or radial deviation as far as degrees of movement? Which is ab vs ad?
Ulnar deviation (30 degrees) [adduction] > Radial Deviation (20 degrees) [abduction]
________ inferior ulnar collateral courses ______ to the trochlea?
Ulnar nerve passes posterior to the medial epicondyle with the superior ulnar collateral artery. Inferior ulnar collateral artery courses anterior to the medial epicondyle
___ nerve passes posterior to medial epicondyle with the superior ulnar collateral artery?
Ulnar nerve passes posterior to the medial epicondyle with the superior ulnar collateral artery. Inferior ulnar collateral artery courses anterior to the medial epicondyle.
Fracture at medial epicondyle could mean damage to what nerve/artery?
Ulnar nerve/artery
****Anterior Forearm: Superficial flexor/pronator group share a proximal attachment to medial epicondyle via _______?
****Anterior Forearm: Superficial flexor/pronator group share a proximal attachment to medial epicondyle via a common flexor tendon (CFT)
Abductor pollicis longus
5. Abductor pollicis longus P: interosseus membrane; proximal radius and ulna D: base of metacarpal I Deep group: Outcropping muscles (to thumb and index finger)
Colles Fracture
A fall onto an outstretched arm and extended wrist may result in a fracture of the distal radius. In this fracture the distal fragment of the radius moves dorsally resulting in a characteristic dinner fork deformity.
A radial arterial pulse can be located lateral to the tendon of ___________ just proximal to the wrist.
A radial arterial pulse can be located lateral to the tendon of flexor carpi radialis just proximal to the wrist.
Writs abduction/adduction what plane?
Abduction/adduction occur in the coronal plane.
Superficial Palmar arch and deep palmar arch
Arterial Networks: Palm of the Hand In general, two palmar arches provide the arterial supply to the hand. The superficial palmar arch is formed mainly by the ulnar a. The deep palmar arch is formed mainly by the radial a.
Arterial supply to the Hand:
Arterial supply to the Hand: Because of its significant functional requirements, the hand is supplied with an intricate network of arterial anastomoses. Therefore, bleeding in the injured hand is profuse.
As the radial nerve exits the arm it innervates brachioradialis and ECRL. Anterior to the lateral epicondyle, the radial nerve branches into:
As the radial nerve exits the arm it innervates brachioradialis and ECRL. Anterior to the lateral epicondyle, the radial nerve branches into: ● deep (motor) branch which innervates ECRB and supinator ● superficial (sensory) branch continues down the forearm toward the anatomical snuffbox
Explain nerve pathway of the nerve of the forearm?
At the cubital fossa (TAN)....median nerve, nerve of the forearm. Travels between the two heads of pronator teres to supply the superficial and intermediate group of forearm flexors except FCU. (PT, FCR, PL, FDS) Continues down the forearm deep to FDS and superficial to FDP. Enters the carpal tunnel with the 9 long flexor tendons. Major branch is the anterior interosseus nerve which supplies the deep anterior forearm group. (1/2 FDP, PQ, FPL).
Fracture of surgical neck could mean damage to what nerve/artery?
Axillary Nerve & Post humeral circumflex Artery
Shoulder joint usual dislocation
Because of its great mobility the shoulder joint is frequently dislocated. Most dislocations occur anteriorly and inferiorly where the fibrous capsule is thinnest and the least stabilized. Anterior/inferior dislocation is usually caused by forceful EXTENSION, LATERAL ROTATION and ABDUCTION such as occurs in throwing sports or a fall on an outstretched arm.
Biceps Brachii
Biceps brachii [C5, C6] P: Long H. #1- supraglenoid tubercle Short H. #2 - coracoid process D: radial tuberosity and bicipital aponeurosis
***How can bleeding of arm be controlled? Why?
Bleeding can be controlled by pressing the axillary or brachial artery against the humeral neck or shaft.
Brachialis
Brachialis #3 [C5, C6] P: distal ½ anterior humerus D: ulnar tuberosity and coronoid process
Radial N. innervates (in posterior arm)
Brachioradialis and ECRL
What is the only muscle of the arm that does not cross the elbow to act on the forearm. (and attachments)*****
Coracobrachialis - only crosses the shoulder [C5.6.7] P: coracoid process D: medial border of humerus Flexes and adducts the humerus
Cubital Fossa (Boundaries)
Cubital Fossa (Boundaries): Roof = bicipital aponeurosis and brachial fascia Medially = pronator teres Laterally = brachioradialis
Graphical Representation (draw) Cutaneous Innervation of the Hand:
Cutaneous Innervation of the Hand:
Deep Branch of Radial N. innvervates (in posterior arm)
ECRB and supinator
Wrist flex/ext in what plane?
Flexion/extension occur in the sagittal plane
_______ flexes the thumb at its most distal joint.
Flexor pollicis longus flexes the thumb at its most distal joint.
MCP extended by _________ PIP joints extended by _________ DIP joints extended by __________
If the MCP joints are extended by extensor digitorum, the PIP joints will now be extended by the intrinsics within the hand via their attachments on the dorsal expansion. Retinacular ligaments then complete full extension of the DIP joints.
Injuries to Ulnar Collateral Ligament
Injuries to Ulnar Collateral Ligament Avulsion of the medial epicondyle can occur during a fall involving excessive valgus stress at the elbow. Traction of the ulnar nerve and superior ulnar collateral artery may be a complication of this type of injury. The ulnar collateral ligament may be overstretched or ruptured from chronic overuse such as in athletic throwing events. Repair and rehabilitation from this injury is a long process (i.e.Tommy Johns Procedure).
What do injuries have to do with the brachial plexus?
Injuries to the brachial plexus will affect movement and sensation in the upper limb. Signs/symptoms will depend on which portion of the plexus is injured.
****what nerve and artery course inferiorly on the medial side of humerus?
Median nerve and brachial artery course inferiorly on the medial side of humerus.
What kind of Metacarpalphalangeal Joint
Metacarpalphalangeal Joint: (Condyloid Jt.) ● Deep transverse metacarpal ligaments ● MCP collateral ligaments ● Loose in extension. Taut in flexion.
****What pierces coracobrachialis and exits lateral arm between brachilais and biceps?
Musculocutaneous n. pierces coracobrachialis and exits lateral arm between brachilais and biceps to become the lateral cutaneous n. of forearm.
_______ and _______ pronate the radius on the ulna.
Pronator teres and pronator quadratus pronate the radius on the ulna.
Midshift fracture could mean damage to what nerve/artery?
Radial Nerve & Deep brachial Artery
Radial collateral ligament
Radial collateral ligament arises from the lateral epicondyle and blends with the annular ligament of the proximal radioulnar joint.
What nerve innervates palmar and dorsal interossei?
Review: 4 dorsal interossei (abductors). 3 palmar interossei (adductors). Remember DAB and PAD. They are arranged around an imaginary line drawn through the long axis of the middle finger. Both palmar and dorsal interossei are innervated by the ulnar nerve.
Saturday night palsy
Saturday night palsy is usually a temporary compression injury to the radial n. (i.e. falling asleep with your arm over the back of a chair).
Features of distal radius
Styloid process Dorsal (Lister's) tubercle
hand, thumb and proximal 1.5 digits...
Superficial Radial Nerve branch courses deep to brachioradialis and emerges near the wrist. It passes superficial to the tendons that form the boundaries of the "anatomical snuffbox". ....and supplies sensation to the radial side of the dorsum of hand, thumb and proximal 1.5 digits.
Deltoid actions on humerus at glenohumeral joint
1. Anterior clavicular fibers flex and medially rotate 2. Middle acromial fibers abduct 3. Posterior (scapular spine) fibers extend and laterally rotate
Hypothenar Compartment: "OAF" to the pinky Flexor digiti minimi brevis
1. Flexor digiti minimi brevis: P: Hook of hamate D: Proximal phalanx
Pronator teres (p/d)
1. Pronator teres: 2 proximal heads P: humeral = CFT + medial epicondyle ulnar = coronoid process D: lateral radius
What two rules does brachioradialus break?
1. the radial n. supplies only extensors 2. all flexors are located in the anterior compartment.
Hypothenar Compartment: "OAF" to the pinky Abductor digiti minimi
2. Abductor digiti minimi P: Pisiform D: Proximal phalanx
Flexor Carpi Radialis (p/d)
2. Flexor Carpi Radialis P: CFT + medial epicondyle D: base of 2nd metacarpal
Glenohumeral Ligaments
3 glenohumeral ligaments (superior, middle, inferior). strengthen the capsule anteriorly The coracohumeral ligament lies superior to the gleno-humeral ligaments and strengthens the capsule superiorly. The coracoacromial arch prevents the traumatic displacement of the humeral head from the glenoid fossa. The tendon of supraspinatus and the subacromial bursa lie under the coracoacromial arch.
Hypothenar Compartment: "OAF" to the pinky Opponens digit minimi
3. Opponens digit minimi P: Hook of hamate D: 5th metacarpal medially
Palmaris Longus
3. Palmaris Longus P: CFT + medial epicondyle D: flexor retinaculum and
Extensor digitorum
4. Extensor digitorum P: lateral epicondyle/CET D: extensor expansion A: extends digits 2-5 Forearm Extensors Superficial group cont.
Flexor Carpi Ulnaris
4. Flexor Carpi Ulnaris: 2 proximal heads P: humeral = CFT ulnar = olecranon D: base of 5th metacarpal, pisiform/hamate
Supinator
4. Supinator P: Humeral head =lateral epicondyle and radial collateral ligament Ulnar head = supinator crest D: proximal 1/3 radius Action: supinates forearm
Extensor digiti minimi
5. Extensor digiti minimi P: lateral epicondyle/CET D: extensor expansion and proximal phalanx of the 5th digit A: extends the 5th digit Forearm Extensors Superficial group cont.
Extensor carpi ulnaris
6. Extensor carpi ulnaris P: lateral epicondyle/CET and posterior ulna D: base of 5 th metacarpal A: extends and adducts hand at the wrist Forearm Extensors Superficial group cont.
Extensor pollicis brevis
6. Extensor pollicis brevis P: interosseous membrane; distal radius D: base of proximal phalanx thumb Deep group: Outcropping muscles (to thumb and index finger)
Flexor digitorum profundus
6. Flexor digitorum profundus P: proximal ulna and interosseus membrane D: distal phalanges 2-5
Extensor pollicis longus
7. Extensor pollicis longus P: interosseous membrane middle ulna D: base of distal phalanx thumb Deep group: Outcropping muscles (to thumb and index finger)
Flexor pollicis longus
7. Flexor pollicis longus P: mid radial shaft D: distal phalanx of thumb
Extensor indicis
8. Extensor indicis P: interosseous membrane distal ulna D: extensor expansion 2nd digit/distal phalanx Deep group: Outcropping muscles (to thumb and index finger)
Pronator quadratus
8. Pronator quadratus P: distal ulna D: distal radius
A thickening of the antebrachial fascia anteriorly is the ________? Lies deep and distal to what ligament?
A thickening of the antebrachial fascia anteriorly is the flexor retinaculum. The flexor retinaculum lies deep and distal to the palmar carpal ligament.
What is the extensor retinaculum? What's its extension called?
A thickening of the antebrachial fascia on the dorsal surface is the extensor retinaculum. The extensor retinaculum retains long extensor tendons coursing into the hand. A portion of extensor retinaculum extends onto the anterior wrist as the palmar carpal ligament
Movements @ humerulnar and humeroradial joints
A. Movements at humeroulnar & humeroradial joints = flexion and extension. B. Movements at the radioulnar joints = pronation and supination
Dorsal Interossei:
ABDUCTION Dorsal Interossei: P: Dorsal interossei are bipennate arising by 2 heads of adjacent metacarpals. D: Insert on the extensor expansion at the base of proximal phalanges in a manner that allows them to abduct the corresponding digit away from the axis at the middle finger. Thus, there are 4 dorsal interossei.
Muscles that extend or abduct the thumb.
Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus
Acromioclavicular Joint: (Plane Joint)
Acromioclavicular Joint: (Plane Joint) ● Articulations: acromion and clavicle ● Fibrous capsule is loose but reinforced by acromioclavicular ligament. ● The joint lends its strength to the coracoclavicular ligament: 1. Anterolateral trapezoid part 2. Anteromedial conoid part.
Flexion and Extension of Lumbricals?
Action of Lumbricals Because of their proximal palmar attachment on the tendons of FDP and their distal attachment on the extensor expansion, lumbricals have the unique ability to both flex the fingers at the MCP joint and yet extend the digits at the PIP joints. Interossei assist the lumbricals in their actions at the MCP and IP joints.
Actions of rotator cuff on humerus
Actions of rotator cuff on the humerus: ● Supraspinatus initiates abduction. ● Infraspinatus laterally rotates. Teres minor laterally rotates. ● Subscapularis (outsider) medially rotates.
Adductor pollicis*****
Adductor pollicis P: Oblique Head: capitate; base of 2nd and 3rd metacarpal Transverse Head: shaft of 3rd metacarpal D: medial proximal phalanx
Radial nerve pathway
After coursing around the spiral groove of the arm the radial n. pierces the lateral intermuscular septum and emerges between brachialis and brachioradialis.
Ulnar Nerve After passing through the ulnar tunnel:
After passing through the ulnar tunnel: Superficial sensory (3) Deep motor branch (4)
After piercing the supinator the deep branch terminates Where?
After piercing the supinator the deep branch terminates as the posterior interosseus nerve (C7,C8)
An injury to the radial neve within the forearm may be specific to which nerves/branches?
An injury to the radial neve within the forearm may be specific to the deep branch of the radial n. or to its terminal branch, the posterior interosseous n.
Anconeus
Anconeus #4 P: posterior humerus/lateral epicondyle D: olecranon and proximal ulna
Another common site for entrapment of the median nerve is within ______ ______. What would clinical presentaton include?
Another common site for entrapment of the median nerve is within the two heads of pronator teres. Clinical presentation would include: 1.Distal signs of carpal tunnel Plus: 4. Loss of sensation in proximal palm (i.e. palmar cutaneous branch) 5. Loss of pronation (PT, PQ) 6. Weakness in radial deviation (FCR) 7. Weakness in wrist flexion (FCR,FDS) 8. Loss of flexion of the middle phalanx at all digits (FDS) 9. Loss of flexion of the distal phalanx at the index and middle fingers (1/2 FDP) 10. Loss of thumb opposition, flexion; weakness of abduction (thenar muscles, FPL)
Muscles of the Arm (flexors/extensors):
Anterior Compartment/Flexors = Biceps brachii Brachialis Coracobrachialis Posterior Compartment/Extensors = Triceps Anconeus
What would happen if only the anterior interosseous branch of the median nerve was compressed by pronator teres.?
Anterior Interosseous Syndrome "pad to pad" instead of "tip to tip"
Olecranon bursitis
As in the shoulder the region around the elbow contains bursae which reduce friction between skeletal and connective tissue structures. An olecranon bursa lies between the triceps tendon and the olecranon process of the ulna as well as between the ulna and skin.
Distal Radioulnar and Radiocarpal (Wrist) Joints.
At the distal radioulnar joint, a fibrocartilagenous articular disc binds the ends of the ulna and radius together. This disc separates the cavity of the distal radioulnar joint from the cavity of the radiocarpal joint (i.e. wrist joint). Wrist (condyloid) jt. is the articulation between radius and carpal bones (scaphoid and lunate). During ulnar deviation of the wrist (radiocarpal joint), the disc contacts the triquetrum. Thus, the articular disc participates at two joints.
****What nerve and artery course posteriorly around the surgical neck of the humerus?
Axillary nerve and post. humeral circumflex artery course posteriorly around the surgical neck.
Signs/Symptoms of Axillary Nerve damage
Axillary nerve injury can occur with fractures at the surgical neck of the humerus. Motor Loss: Severe weakness in abduction - deltoid Weakness in lateral rotation - teres minor and posterior fibers of deltoid Sensory Loss: Injury to the axillary nerve may result in loss of sensation to a small area of skin that is exclusively supplied by the axillary nerve. The posterior humeral circumflex artery (3rd part of axillary a. travels with the axillary nerve near the surgical neck of the humerus.
Which muscle of the arm only crosses shoulder?
Both heads of the biceps brachii cross two joints, the shoulder and the elbow. The brachialis only crosses the elbow. The coracobrachialis only crosses the shoulder.
Medial and lateral intermuscular septa are what?
Brachial fascia is a continuation of axillary, deltoid, pectoral and infraspinatus fascia. This deep fascia encloses the arm like a sleeve. Brachial fascia extends from the axilla to the epicondyles of the humerus. Medial and lateral intermuscular septa are extensions of the deep brachial fascia.
Bursae & major bursae of shoulder
Bursae are flattened sacs containing synovial fluid that reduce friction as tendons pass around a joint. Inflammation of a bursa is called "bursitis". Bursae are very important structures in the shoulder region.
The biceps tendon reflex test is used to test the integrity of what spinal segments?
C5 & C6 Injury to the musculocutaneous n. is rare but would result in: 1. Decreased or absent bicep tendon reflex (C5,C6) 2. Loss of sensation along the lateral forearm 3. Weakness in arm flexion 4. Severe weakness of forearm flexion 5. Weakness in forearm supination
Triceps innervation origins in spinal cord?
C6, C7, C8
Ulnar nerve has what spinal cord origins? What's the path it takes?
C7, C8, T1 In the arm travels with the superior ulnar collateral artery. Both course posterior to the medial epicondyle ("funny bone") to exit the arm. Enters the forearm between the two heads of flexor carpi ulnaris. Supplies FCU and ½ FDP. Continues with the ulnar artery deep to FCU to enter the ulnar canal ("Guyon's tunnel").
Names of condyles of humerus*****
Capitulum & Trochlea Capitulum = lateral CONDYLE Trochlea = medial CONDYLE
Carpal bones are divided into proximal and distal rows: name bones
Carpal bones are divided into proximal and distal rows: Scaphoid is frequently fractured. Lunate is moon shaped. Triquetrum has "three corners". Pisiform is a sesamoid bone. Trapezium articulates with base of metacarpal I (thumb). Trapezoid articulates with base of metacarpal II Capitate is the largest. Articulates with base of metacarpal III. Hamate has a hook.
Carpometacarpal Joints
Carpometacarpal Joints: Digits II-V (Plane jts) Articulation between trapezium and base of metacarpal #1 is a saddle joint.
Thoracic Outlet Syndrome
Cause: Constriction or pressure to subclavian artery and/or portions of brachial Plexus within the thoracic outlet by scalene muscles, pectoralis minor or cervical rib. Symptoms would depend on the portion of the brachial plexus that was affected. A reduction of pulse pressure may also be noted on the affected side.
Collaterals in arm
Collateral circulation at the elbow involves anastomoses between collateral and recurrent arteries: Collaterals in Arm Pofunda brachii artery laterally yields the middle and radial collateral arteries. Brachial artery medially yields the superior and inferior ulnar collateral arteries.
Forearm: Arterial Supply
Common interosseous branch of the ulnar artery arises in the distal part of the cubital fossa and divides into: ►anterior interosseous artery ►posterior interosseous artery These interosseous arteries travel along the interosseous membrane to supply the muscles of the deep forearm.
Cutaneous peripheral distribution to the arm:
Cutaneous peripheral distribution to the arm: Supraclavicular n. (C3,4 ventral rami cervical plexus) - over the shoulder Axillary n. (posterior cord) - posterior and lateral surfaces of superior arm Radial n. (posterior cord) - posterior and lateral arm below axillary distribution Intercostal brachial cutaneous n. (T2 ventral rami) - medial arm and axilla Medial brachial cutaneous n. (medial cord) - medial arm
Name of the fascia separating flexors and extensors in arm?
Deep fascia is a continuation of brachial fascia and called antebrachial fascia. Thickenings of the antebrachial fascia at the wrist maintain the long tendons of the forearm as they course to distal attachments in the hand.
Shoulder separation
Dislocation of the acromioclavicular joint is often referred to as a shoulder separation. It may involve fracture of the clavicle as well as the rupture of one or both coracoclavicular ligaments.
Expansions and Hoods
Distal to their intertendinous connections along the dorsal phalanges, the tendons of EDL flatten to form extensor expansions. EI and EDM send slips into this expansion. Each individual expansion wraps around a metacarpal head and its proximal phalanx. These dorsal "hoods" maintain the extensor tendons in the middle of each digit. Each expansion gives rise to two lateral and one median band(s).
During dissection, one can locate the recurrent branch of the median nerve as it passes superficial to ____ _____ _____.
During dissection, one can locate the recurrent branch of the median nerve as it passes superficial to Flexor Pollicis Brevis.
Elbow movement
During extension, olecranon fossa of humerus contains the olecranon process of ulna. Capitulum of humerus articulates with head of radius. At end range flexion, radial head contacts radial fossa of humerus. Trochlea of humerus articulates with trochlear notch of ulna. At end range flexion, coronoid process of ulna contacts coronoid fossa of humerus.
Each tendon of flexor digitorum ______ attaches to the distal phalanx of digits 2-5. FDP tendons travel between the split tendons of FDS.
Each tendon of flexor digitorum profundus attaches to the distal phalanx of digits 2-5. FDP tendons travel between the split tendons of FDS.
Each tendon of flexor digitorum _______ splits to attach to the middle phalanx of digits 2-5.
Each tendon of flexor digitorum superficialis splits to attach to the middle phalanx of digits 2-5.
Elbow Joint: (Hinge Joint)
Elbow Joint: (Hinge Joint) ● Articulations: Humeroulnar and humeroradial joint Humeroulnar = trochlear of humerus with trochlear notch of ulna Humeroradial = capitulum of humerus with head of radius ● Fibrous capsule is strengthened laterally by the radial collateral ligament and medially by the ulnar collateral ligament.
Posterior view/notes of elbow joint
Epi = "on top of" Medial epicondyle Lateral epicondyle Supracondylar ridges Medial Lateral Note: ulnar groove inferior to the medial epicondyle
Muscles that extend and abduct (radial deviation) or adduct (ulnar deviation) the hand at the wrist.
Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris Full abduction/adduction of the wrist requires action by both flexors and extensors.
Muscles that extend the digits, excluding the thumb.
Extensor digitorum Extensor indicis Extensor digiti minimi
Entire Extensor mechanism overview
Failure of any of these structures will result in deformity and loss of function. 1. Active muscle contraction of extensor digitorum to extend the MCP joint. 2. Active muscle contraction of the intrinsics (i.e. lumbricals and interossei) which course from the palmar surface to attach to the extensor expansion. 3. An intact extensor expansion by which these intrinsics can extend the PIP joints. 4. Engagement of the retinacular ligaments which coordinate flexion and extension between the PIP and DIP joints.
What are the 5 fascial compartments in the hand?
Fibrous septums extend from the palmar aponeurosis creating five fascial compartments within the hand. Central compartment (pink) contains the long flexor tendons and lumbricals. Thenar compartment (orange) contains muscles that move the thumb (OAF). Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis Adductor compartment (purple) contains one additional muscle that moves the thumb: Adductor pollicis brevis Hypothenar compartment (blue) contains the muscles that move the little finger (OAF). Opponens digiti minimi Abductor digiti minimi Flexor digiti minimi brevis Interosseous compartment (brown)
______ and_____ act as strong wrist flexors.
Flexor carpi radialis and flexor carpi ulnaris act as strong wrist flexors. Individually, they complete radial deviation (abd.) or ulnar deviation (add.).
_______ and ________both flex the digits but at different joints.
Flexor digitorum superificalis and flexor digitorum profundus both flex the digits but at different joints.
Brachioradialis
Forearm Extensors Superficial group: 1. Brachioradialis (C5, C6) P: lateral supracondylar ridge D: styloid process of radius A: flexes neutral forearm at elbow Forms the lateral border of the cubital fossa. Helpful to use brachioradialis as a landmark when naming the muscles of the forearm. Deep tendon reflex at tendon insertion at styloid process tests the integrity of the radial nerve as well as the C6 spinal segment. While brachioradialis is located in the posterior compartment and is innervated by the radial nerve, it functions as a flexor of the forearm.
Extensor carpi radialis longus
Forearm Extensors Superficial group: 2. Extensor carpi radialis longus P: lateral supracondylar ridge D: base of 2nd metacarpal Action: extends and abducts hand at wrist
Extensor carpi radialis brevis
Forearm Extensors Superficial group: 3. Extensor carpi radialis brevis P: lateral epicondyle (common extensor tendon = CET ) D: base of 3rd metacarpal Action: extends and abducts hand at wrist
T or F functionally the antebrachium includes the distal humerus?
Functionally, includes the distal humerus since many of the muscles acting on the forearm and hand have their proximal attachments on the distal humerus. The muscles of the forearm are unique in that many have long tendons which act like pulleys providing maximal control over multiple joints in the wrist and hand. As in the arm, deep fascia divides the forearm into anterior/posterior compartments.
Glenohumeral Joint:
Glenohumeral Joint: Because of the looseness of the capsule and ligaments, the chief stability for the shoulder must come from the muscles surrounding the joint. Supraspinatus - superiorly Infraspinatus - posteriorly Teres minor - posteriorly Subscapularis - anteriorly Recurrent inflammation and/or impingement of the tendons as they pass under the coracoacromial arch may lead to chronic tendonitis. Tendon of biceps enclosed NOT TRICEPS
Movements at the elbow involve the articulations between the humerus, radius and ulna. Three joints are involved. What are they?
Humero-ulnar joint is a true elbow joint (hinge)
If the deep branch of the radial n. is intact post-injury what tendons would you expect to see? (dorsum)
If the deep branch of the radial n. is intact, the long extensor tendons should appear prominently on the dorsum of the hand during MCP extension (ED).
Muscle testing for FDS vs FDP how?
In muscle testing, one can isolate FDS from FDP by knowing their distal attachment sites.
Injury to the lower portion of the brachial plexus
Injury to the lower portion of the brachial plexus (C8,T1) may result from traumatic separation of the upper limb from the trunk. (i.e. Klumpke Paralysis and a claw hand position of the upper limb.) A claw hand deformity results from an isolated contraction of extensor digitorum resulting in hyperextension of the MCP joint. The short intrinsics are unavailable (C8,T1) to counter the forces of ED at the MCP joint or achieve full IP extension during attempts to extend the fingers.
Injury to the median nerve at or above pronator teres may also result in what clinical malformation?
Injury to the median nerve at or above pronator teres may also result in a clinical "Hand of Benediction". When a patient is asked to make a fist, the intact ulnar nerve (ulnar suppplied ½ FDP) would allow the ring and little fingers to flex distally. The middle and index fingers would remain partially extended. (median supplied ½ FDP now lost).
Injury to the musculocutaneous n. is rare but would result in:
Injury to the musculocutaneous n. is rare but would result in: 1.Decreased or absent bicep tendon reflex. (This reflex also tests the integrity of the C5,C6 spinal segments.) 2. Loss of sensation along the lateral forearm - lat. antebrachial cut. n. 3. Weakness in arm flexion - biceps brachi, coracobrachialis 4. Severe weakness of forearm flexion - biceps brachi, brachialis 5. Weakness in forearm supination - biceps brachi
Injury to the upper portion of the brachial plexus (C5/C6)commonly results from what? how is it clinically presented?
Injury to the upper portion of the brachial plexus (C5,C6) may result from traumatic separation of the neck from the shoulder. The usual clinical presentation is an upper limb held at the side with the shoulder medially rotated. This occurs because the patient is unable to flex, abduct or laterally rotate the shoulder. The patient will also experience loss of sensation along the lateral portion of the upper limb (C5,C6 dermatome). The clinical presentation is called the waiter's tip position of the upper limb and the condition is called Erb Duchenne Palsy.
Segmental innervation for all intrinsics of the hand
Innervation: C8,T1 Segmental innervation for all intrinsics of the hand
Scapulohumeral muscles innervated by branches of posterior cord;
Innervation: Scapulohumeral muscles are innervated by branches of the posteror cord: (ULTRA) Subscapularis (C5,C6,C7) upper subscapular nerve lower subscapular nerve Teres Major (C5,C6,C7) lower subscapular nerve Deltoid & Teres Minor (C5,C6) axillary nerve
Posterior extensor/supinator forearm group is innervated by what?
Innervation: radial nerve Formed by posterior divisions.
Interossei: _ dorsal and _ palmar arranged around axis located through middle phalanx
Interossei: 4 dorsal and 3 palmar arranged around axis located through middle phalanx
What kind of joint is the interphalangeal jt?
Interphalangeal Joints (Hinge Jts): ● Palmar and Collateral Ligaments
Motions in the Hand (4 jt types)
Interphalangeal Jts (PIP,DIP) - hinge jts allow flex/extension Metacarpophalangeal Jts (MCP) Heads of metacarpals ("knuckles") with bases of proximal phalanges - condyloid jts allow flex/extension and abd/adduction Carpometacarpal Jts (CMC) [arrow in pic] Distal carpal bones with bases of metacarpals - CMC digits II-V are plane jts - CMC digit I (thumb) is a saddle jt which allows flex/extension and abd/adduction Intercarpal/Midcarpal Jts plane jts which augment movements at more distal joints
Muscle of the Intrinsic Scapulohumeral Group
Intrinsic Scapulohumeral Group: No attachment to the axial skeleton. Deltoid Supraspinatus Infraspinatus Teres Minor Subscapularis* Teres Major
INtrinsic finger muscle movements
Intrinsic muscles within the hand assist the actions of extensor digitorum. Although they arise from the palmar surface of the hand, these intrinsics have distal attachments to the extensor expansion. After extensor digitorum extends the MCP joint it has less tensile force to extend more distal joints (PIP,DIP). The intrinsics are able to extend these distal joints thru their attachment to the extensor expansion.
Joints of the Upper Extremity Sternoclavicular Joint: (Saddle Joint)
Joints of the Upper Extremity Sternoclavicular Joint: (Saddle Joint) ● Articulations = manubrium, clavicle, 1st costal cartilage ● Articular disc of fibrocartilage divides the joint into two parts. ● Elevation/depression; protraction/retraction; rotation ● Participates in scapulohumeral rhythm increasing range of upper limb. ● Dislocation rare. The clavicle is usually fractured before it is displaced.
What muscle would be impacted by a thoracodorsal nerve injury?
Latissimus dorsi is innervated by the thoracodorsal n. (C6,C7,C8) from the posterior cord. The thoracodorsal n. may also be injured during resection of tumors within the axilla. With injury to the thoracodorsal n. a patient would find it difficult to push off from the edge of a bed or chair and find it difficult to use axillary crutches.
Anterosuperior Tear
Laxity of the anterior capsule from chronic displacement may result in the humeral head being chronically driven into the labrum and result in labral tears. Anterosuperior tears of the labrum often occur in athletes involved in throwing sports and may involve the long head of the biceps tendon (i.e. slap tear)
What is the purpose of the transverse humeral ligament?
Long head of the biceps tendon traverses the intertubercular sulcus. It is held in place by the transverse humeral ligament. You can palpate the tendon during medial and lateral rotation of the humerus. Biceps tendonitis is a common injury in racquet and throwing sports. Rupture of the tendon is can occur ("popeye" deformity).
Can you name the three muscles that have a proximal attachment at the corocoid process of the scapula?
Look em up
What is froment's sign?
Loss of thumb adduction (adductor pollicis)
Lumbrical attachment and action
Lumbricals D: Pass to the radial side of the corresponding finger and insert onto the radial border of the extensor expansion Actions: Lumbricals and interossei attach to aspects of the extensor expansion. Muscles which attach to the expansion can extend PIP joints of the digits via the expansion.
Which lumbricals have a single head? Which are innervated by the median nerve?
Lumbricals I and II have a single head and are innervated by the median n. Lumbricals III and IV may have two heads and are innervated by the ulnar n.
Lumbricals
Lumbricals arise from the tendons of flexor digitorum profundus and thus lie within the central compartment of the hand along with the long flexor tendons. There are 4 tendons of FDP and thus 4 lumbricals.
Lumbricals cross________ to the deep transverse metacarpal ligament. Interossei cross________ to the deep transverse metacarpal ligament.
Lumbricals cross ventral to the deep transverse metacarpal ligament. Interossei cross dorsal to the deep transverse metacarpal ligament.
On inspection of the hand, the contours of the muscles of the thenar and hypothenar compartments can be easily observed
Many of the muscles of the thenar and hypothenar compartments have a superficial proximal attachment to the flexor retinaculum.
Peripheral Nerve Innervation (medial, lateral and posterior cutaneous nerve of the forearm)
Medial Cutaneous n. of forearm → from medial cord Lateral Cutaneous n. of forearm → terminal branch of musculocutaneous n. Posterior Cutaneous n. of forearm → branch of radial n.
Origin of common palmar nerves
Medial and Lateral branches innervate lumbricals I and II and then divide into common palmar digital nerves. Common palmar digital nerves become proper palmar digital nerves which supply the palmar surface of the thumb and adjacent 2 1/2 digits.
Median N (hand intrisics)
Median N. = ½ LOAF Thenar Compartment ½ Lumbricals
median nerve pathway into hand
Median Nerve Prior to entering the hand, a palmar cutaneous branch of the median nerve emerges to run superficial to the flexor retinaculum. This branch supplies the skin of the central palm. The median nerve then enters the palm deep to the carpal tunnel.
The most common injury to the median nerve occurs where?
Median Nerve: The median nerve may be injured anywhere in its course. The most common injury to the median nerve occurs distally at the carpal tunnel.
Median nerve has what spinal cord origins?
Median nerve (C5,C6,C7,C8,T1)
Metacarpal and digit numbering
Metacarpals and digits are numbered I-V. Each metacarpal and individual phalanx consist of a shaft which connects a proximal base to a distal head.
Important concept regarding whether or not forearm muscles can fully function at multiple joints at the same time
Most forearm muscles cross multiple joints. A characteristic of multiple joint muscles is that they are not long enough to fully function at both joints at the same time. In other words, if a muscle functions to flex both the wrist as well as the digits, it will not be able to maximally flex the digits if it is already involved in wrist flexion.
Axillary nerve injury can occur with fractures at what? What signs/symptoms would result?
Motor Loss: Severe weakness in abduction - deltoid Weakness in lateral rotation - teres minor Sensory Loss: The axillary n. has sensory branches that supply a portion of the superior and lateral arm. Injury to the axillary n. would result in parathesia in this area.
Radial Nerve motor injury
Motor Loss: Weakness in forearm flexion (brachioradialis) Inability to extend wrist and weakness in radial and ulnar deviation (ECRL,ECRB,ECU) Weakness of supination (S) Inability to extend digits (ED, EDM,EI) Inability to extension the thumb (EPL,EPB) Weakness in abduction of the thumb (APL)
Ulnar Bursa and Radial Bursa
Nine tendons course deep to the flexor retinaculum within the carpal tunnel. To reduce friction within the tunnel, the "stacked" tendons of FDS/FDP are surrounded by a synovial sheath, the "ulnar bursa". These eight tendons enter the central compartment of the hand and fan out to enter their respective synovial digital sheaths. The single tendon of flexor pollicis longus (FPL) travels in its own synovial sheath or "radial bursa". Fibrous digital sheaths enclose the flexor tendons and their synovial sheaths and maintain them against the underlying bone.
Opposition and reposition of thumb means what?
Opposition of thumb and little finger is a combination of flexion, adduction and circumduction over multiple joints.
Anterior Forearm: Intermediate muscle Flexor Digitorum Superficialis
P: Humero-ulnar head: medial epicondyle and proximal ulna Radial head: oblique line D: 2 slips on each side of middle phalanges 2-5
Palmar Interossei
P: Palmar interossei are unipennate, arising by a single head from each metacarpal. D: Insert into the extensor expansion at the base of proximal phalanges in a manner that allows them to adduct the digit toward the axis at the middle finger. Thus, there are 3 palmar interossei.
Deltoid
P: lateral clavicle, acromion & spine of scapula D: deltoid tuberosity of humerus
_______ is a very weak wrist flexor. In fact, it is often not repaired when torn.
Palmaris longus is a very weak wrist flexor. In fact, it is often not repaired when torn.
What is the innervation of the posterio forearm? Where does it originate?
Posterior Forearm Innervation: Radial Nerve (C5,C6,C7,C8,T1)
Ulnar Nerve Prior to entering the ulnar tunnel:
Prior to entering the ulnar tunnel: Palmar cutaneous branch (1) Dorsal cutaneous branch (2)
Proximal Attachments of rotator cuff muscles
Proximal Attachments: 1. Supraspinatus - supraspinous fossa 2. Infraspinatus - infraspinous fossa 3. Teres Minor - lateral border scapula 4. Subscapularis - subscapular fossa
Ulnar Nerve injury commonly occurs at four anatomical sites, what are they?
Proximal Injury 1.medial epicondyle 2.cubital fossa between the heads of FCU Distal Injury 3.ulnar tunnel (i.e. ulnar canal syndrome) 4.within the hand Injury at the elbow would result in: 1.Weakness of wrist flexion and ulnar deviation (FCU) 2.Loss of flexion of the distal phalanges of ring and little fingers ulnar ½ FDP) 4. Loss of abduction, adduction of fingers at MCP joints (interossei) 5. Loss of thumb adduction (adductor pollicis) (Froment's Sign) 6. Atrophy and loss of fuction of hypothenar muscles (FDMB,ADM,ODM) 7. Loss of sensation over ulnar side of hand (palmer and dorsal surface) and 1 ½ fingers 8. Failure of the fingers to flex at the MCP or extend at IP joints, especially ring and little finger. (interossei and lumbricals) producing an "ulnar claw" hand.
Proximal Radioulnar Joint: (Pivot Joint)
Proximal Radioulnar Joint: (Pivot Joint) The annular ligament maintains the head of the radius within the radial notch of the ulna. The deep surface of the annular ligament is lined with a synovial membrane which continues distally as a recess onto the neck of the radius. This arrangement allows the radius to rotate freely within the annular ligament.
Proximal to the knuckles (MCP joints) the tendons of extensor digitorum are linked by ______#_______ (how many?) intertendinous connections that restrict independent extension of the fingers.
Proximal to the knuckles (MCP joints) the tendons of extensor digitorum are linked by 3 intertendinous connections that restrict independent extension of the fingers. Consequently, no finger can remain fully flexed as the others are fully extended.
What makes up the "quadrangular space"
Quadragular space defined by the teres minor, teres major, long head of triceps and lateral head of triceps. The quadrangular space transmits the axillary n. and posterior humeral circumflex a.
What nerve and artery course posteriolaterally around the humeral shaft at the spiral groove?
Radial nerve and deep brachial artery course posteriolaterally around the humeral shaft at the spiral groove.
Wrist joint or the ____joint
Radiocarpal jt. Wrist ("carpus") is the junction of the forearm and the hand Wrist Joint = radiocarpal joint Condyloid joint formed as distal concave surface of radius articulates with two carpal bones, the scaphoid and lunate.
Radioulnar Joints:
Radioulnar Joints: Proximal and Distal = pivot joints Middle = syndesmosis (interosseous membrane) Together, allow rotation of the radius on the ulna for pronation and supination. Head of radius pivots on the radial notch of ulna proximally (within annular ligament).
Recurrents in Forearm
Recurrents in Forearm Radial artery laterally yields a radial recurrent artery. Ulnar artery medially yields anterior and posterior ulnar recurrent arteries.
_________ extends from the shoulder to the elbow.
Region = Arm or Brachium extends from the shoulder to the elbow.
Posterior Interosseous N. innervates
Remaining muscles of the posterior compartment
Remember 3 nerves and the arteries they travel with: Median = Ulnar = Radial =
Remember 3 nerves and the arteries they travel with: Median = brachial artery in the arm Ulnar = superior ulnar collateral artery (arm) and ulnar artery(forearm) Radial = deep brachial a. (arm)
Remember 3 nerves and the muscles they pierce (i.e. heads): Median. Ulnar Radial
Remember 3 nerves and the muscles they pierce (i.e. heads): Median. = Pronator Teres Ulnar = Flexor Carpi Ulnaris Radial = Supinator
What branch as way to distinguish damage to ulnar n. at wrist or at a site proximal to the wrist?
Remember dorsal cutaneous branch as way to distinguish damage to ulnar n. at wrist or at a site proximal to the wrist.
Remember that the anterior interosseus n. is a branch of the __________ and that the posterior interosseus n. is a branch of the __________
Remember that the anterior interosseus n. is a branch of the median n.and that the posterior interosseus n. is a branch of the radial n. They travel on the interosseus membrane with the artery of the same name (branches of common interosseus artery supplied by the ulnar artery.).
Remember what muscle the nerves travel deep to in the forearm: Median = Ulnar = Radial (superficial branch) =
Remember what muscle the nerves travel deep to in the forearm: Median = deep to FDS and superficial to FDP Ulnar = deep to FCU Radial (superficial branch) = deep to Brachioradialis
Explain tennis elbow
Repetitive use of the superficial extensors of the forearm can result in inflammation of the common extensor tendon. The supinator may also be involved. This condition is called lateral epicondylitis ("tennis elbow").
Reproduction of Carpal Tunnel Symptoms:
Reproduction of Carpal Tunnel Symptoms: 1.Primary sign is pain and/or parasthesia within the distal palm and palmar surface of 3½ digits. Sensation in the proximal palm would be intact. (palmar cutaneous branch does not enter tunnel). 2.Motor weakness can occur "1/2 LOAF". 3.Thenar atrophy and long term loss of strength can occur if the compression is not alleviated. Treatment is usually a resting splint and physical therapy as well as eliminating the cause of the inflammation. Surgical release of the flexor retinaculum may be necessary in difficult cases.
Retinacular Ligaments and cooperative movement
Retinacular ligaments run obliquely from the digital sheaths on the palmar surface to the lateral bands of the extensor expansion on the DORSAL surface. During flexion of DIP joints, the retinacular ligaments become taut pulling the PIP joints into flexion. Similarly, on extending PIP joints, the DIP joints are pulled by the retinacular ligament into extension. Thus, retinacular ligaments coordinate flexion and extension between the PIP and DIP joints.
Rotator tears most often involve what muscle?
Rotator cuff tears most often involve the supraspinatus tendon as it courses inferior to the acromion process. The patient would have difficulty initiating abduction. The patient would not be able to sustain abduction secondary to pain.
Cross section Glenohumeral Joint (high yield)
Rotator cuff tendons blend into the shoulder capsule and stabilize the joint:
What two bones of the hand does the radiocarpal jt articulate with?
Scaphoid and Lunate
Radial Nerve sensory loss injury...loss of sensation where?
Sensory Loss: Reduced sensation on the posterior forearm and dorsum of the hand
Injury to serratus anterior can impact what nerve?
Serratus anterior is called the "boxer's muscle. Injury to the serratus anterior or the long thoracic nerve can result in a "winged scapula".
____________ of the hand are located within the central compartment and the interosseous compartment.
Short intrinsics of the hand are located within the central compartment and the interosseous compartment. The short intrinsics include the lumbricals and interossei.
Shoulder (Glenohumeral) Joint: (Ball and Socket Joint)
Shoulder (Glenohumeral) Joint: (Ball and Socket Joint) ● Articulations: glenoid cavity of scapula and head of humerus. ● The glenoid cavity is deepened by a fibrocartilagenous rim, the glenoid labrum. ● Superiorly, the labrum is continuous with the tendon of the long head of the biceps. GLenoid Labrum fibrocartilage is continuous with the long head of the biceps (she loves to ask this)
Take time to draw cross section of hand/wrist
Structures coursing into the palm from the forearm are "extrinsic" to the hand. We will now focus on structures "intrinsic" to the hand (i.e. both proximal/distal attachments are within the hand).
Features of distal ulna
Styloid process Head
Summary: Radioulnar joints
Summary: Radioulnar joints (pronation/supination) Proximal radioulnar joint is a pivot joint (annular ligament). Middle radioulnar joint is a fibrous syndesmosis. Distal radioulnar joint is also a pivot joint. Palmar and dorsal radioulnar ligaments and a fibrous articular disc bind the radius and ulna together.
What structures are superficial to anatomical snuffbox what structures are deep?
Superficial structures: Superficial radial nerve Cephalic vein Deep structures: Scaphoid Trapezium Radial artery
ARMY/NAVY
Suprascapular artery travels with the suprascaplar nerve superior and inferior to the superior transverse scapular ligament, respectively ("ARMY over NAVY") Suprascapular artery usually originates from the thyrocervical trunk. Suprascapular structures can be compressed within the scapular notch. Shoulder abduction and external (lateral) rotation would be affected.
Innervation/Arterial Supply (rotator cuff)
Suprascapular nerve (C5,C6) arises from the superior trunk. Courses through the scapular notch to innervate supraspinatus. Continues around spinoglenoid notch to innervate infraspinatus.
What branch arises prior to the carpal tunnel and can be used to distinguish between lesions within the tunnel versus lesions of the median nerve at more proximal sites?
Symptoms occur when the size of the tunnel is reduced (i.e. inflammation). Note that the palmar cutaneous branch arises prior to the tunnel and can be used to distinguish between lesions within the tunnel versus lesions of the median nerve at more proximal sites.
Cubital Fossa - TAN
TENDON ARTERY NERVE Tendon of Biceps Brachial Artery Median Nerve
Teres Major Actions on Humerus:
Teres Major Actions on Humerus: Adducts Medially rotates
Anterior forearm compartment innervated primarily by what nerve?
The anterior compartment is innervated primarily by the median nerve or one of its branches. The ulnar nerve supplies one and ½ muscles. The muscles of each forearm compartment are innervated by peripheral nerves derived from anterior and posterior divisions of the brachial plexus.
The anterior flexor-pronator group of the forearm is further divided into how many groups? What are they?
The anterior flexor-pronator group of the forearm is further divided into 3 groups: superficial, intermediate and deep.
The apex of the palmar aponeurosis liessuperficial to what two structures?
The apex of the palmar aponeurosis lies superficial to the palmar carpal ligament and flexor retinaculum.
Actions of the biceps brachii and brachialis
The biceps is the strongest supinator of the forearm when the elbow is flexed. The biceps is the strongest flexor of the forearm when the forearm is supinated. Otherwise, the brachialis is the strongest forearm flexor. The action of the biceps brachii: supination and flexion of forearm (i.e. "pulling out a wine cork") To isolate the brachialis from the biceps brachii in muscle testing, one would place the forearm in maximal pronation, thus eliminating the ability of the biceps to function as a strong elbow flexor.
The ______ artery divides in the cubital fossa into the radial and ulnar arteries.
The brachial artery divides in the cubital fossa into the radial and ulnar arteries.
The carpal groove is transformed into a carpal tunnel by what?
The carpal groove is transformed by the flexor retinaculum into a carpal tunnel. Nine long flexor tendons and the median nerve use the carpal tunnel to gain access into the hand.
The deep palmar arch gives rise to:
The deep palmar arch gives rise to: 1. palmar metacarpal branches 2. princeps pollicis branch 3. radialis indicis branch Prior to winding around the wrist, the radial artery contributes a small superficial palmar branch to the superficial palmar arch.
What prevents the bowstringing of long extensor tendons?
The extensor retinaculum prevents bowstinging of the long extensor tendons at the wrist when the hand is extended. 12 extensor tendons (9 muscles) travel in 6 synovial sheaths under the extensor retinaculum. The tendon of EI joins the four tendons of ED to pass deep to the extensor retinaculum thru a common extensor synovial sheath and osseofibrous tunnel. The remaining tendons travel in individual synovial sheaths and osseofibrous tunnels.
The fascia of the palm is thickened centrally by________
The fascia of the palm is thickened centrally by a triangular palmar aponeurosis.
Hand fascia review
The fascia of the palm is thickened in several areas: 1. Palmar aponeurosis - expansion of palmaris longus tendon if present. 2. Flexor retinaculum - apex of palmar aponeurosis. Maintains long flexor tendons. 3. Fibrous digital sheaths that enclose the long flexor tendons and their synovial sheaths to form osseofibrous tunnels.
How many bones carpal bones, metacarpals and phalanges?
The hand (i.e. manus) contains carpal bones at the wrist, metacarpals in the hand proper and phalanges in the digits. 8 carpals 5 metacarpals 14 phalanges (3 phalanges for each digit = 12, 2 phalanges for the thumb)
What is ape hand deformity?
The hand would be unable to fully grasp. The thenar muscles of the hand would atrophy and the thumb would be adducted. The hand would lie supinated and deviated to the ulnar side. MCP joint may be hyperextended. This presentation is called an "ape hand deformity".
Vincula
The long flexor tendons are supplied by small blood vessels that pass to them within synovial folds ("mesotendon"s) from periosteal arteries of the phalanges. These folds are called "vincula".
What is tubular sheath, why is it important?
The long head of the biceps tendon passes through the superior edge of the capsule to attach to the supraglenoid tubercle. In fact, the tendon is enclosed by the fibrous layer of the capsule and a synovial membrane forms a tubular sheath around the tendon. The fibrous capsule extends from the labrum as a loose tube. A portion of the capsule extends inferiorly. This redundancy accommodates full abduction of the arm.
What can be injured during surgery removing lymph nodes?
The long thoracic n. (C5,C6,C7) can be injured within the axilla during surgery to remove lymph nodes in cases of breast cancer. The patient will have trouble bringing his arm fully over his head since the serratus anterior is important in stabilizing the scapula on the thoracic wall.
What is the terminal branch of the lateral cord?
The musculocutaneous n. is the terminal branch of the lateral cord. Pierces the coracobrachialis to enter the anterior compartment and innervates all anterior arm muscles. Terminates in the distal arm as the lateral antebrachial cutaneous n.
Deeper supinator muscle & Deepest outcropping group
The outcropping group is so named because the muscles emerge from a furrow along the interosseous membrane.
At its base, the palmar aponeurosis divides into how many longitudinal bands?
The palmar aponeurosis is continuous with an expansion of a long flexor tendon, the palmaris longus. At its base, the palmar aponeurosis divides into four longitudinal bands which extend to each finger as well as transverse bands that reinforce the aponeurosis proximally
What do the palmar carpal ligament and flexor retinaculum do?
The palmar carpal ligament and the flexor retinaculum retain the long flexor tendons as they course into the hand within the carpal groove. The flexor retinaculum is attached medially to the pisiform and hamate and laterally to the scaphoid and trapezium.
Posterior compartment innervated primarily by what nerve?
The posterior compartment is innervated by the radial nerve or one of its branches. The muscles of each forearm compartment are innervated by peripheral nerves derived from anterior and posterior divisions of the brachial plexus.
the radial artery exits the forearm...
The radial artery leaves the forearm by winding around the lateral side of the wrist to enter the anatomical snuffbox.
Radial Artery Pathway
The radial artery leaves the forearm by winding around the lateral aspect of the wrist. The radial artery then crosses the floor of the anatomical snuffbox and enters the palm by coursing first between the two heads of the 1st dorsal interossei and then the two heads of adductor pollicis to enter the palm and form the Deep Palmar Arch.
What is the terminal branch of the posterior cord?
The radial nerve is the terminal branch of the posterior cord: - Innervates tricep and anconeus. Provides cutaneous branches to the posterior and inferior lateral arm. - Travels with the deep (profunda) brachial artery at the (radial) groove. - May be damaged by a mid shaft fracture of the humerus.
What muscles of the hand are supplied by the radial nerve?
The radial nerve supplies no muscles in the hand. The superficial branch of the radial nerve emerges in the distal forearm from under brachioradialis and crosses over the anatomical snuffbox. It supplies the skin on the dorsum of the radial side of the wrist, hand, proximal thumb and a portion of 2 ½ digits.
The sensory branch supplies the skin over the palmar surface of how many digits?
The sensory branch supplies the skin over the palmar surface of 1 ½ digits.
What can get entrapped or compressed within the suprascapular notch?
The suprascapular n. (C5,C6) can be entrapped or compressed within the suprascapular notch. Injury would result in an inability to initiate abduction and weakness of external rotation of the arm.
Which bursa communicates with the joint cavity?
The synovial membrane of the joint protrudes through apertures in the fibrous membrane to form bursae. These bursae lie between the tendons of surrounding muscles and the fibrous membrane. The subscapular bursa consistently communicates with the joint cavity and thus inflammation within this bursa can quickly lead to joint damage. Other bursa do not necessarily communicate with the joint cavity but may become irritated secondary to poor joint mechanics
Explain what hand muscles cross tubercle and how that impacts force
The tendon of extensor pollicis longus crosses a tubercle on the distal radius (Lister's tubercle) as it proceeds to its insertion on the distal phalanx of the thumb. This tubercle serves as a pulley which allows a change of direction and thus a mechanical advantage for the muscle.
The tendons of __________ and _________ allow for some degree of independent extension of the index and the little finger.
The tendons of extensor indicis and extensor digiti minimi allow for some degree of independent extension of the index and the little finger.
what defines the anatomical snuffbox?
The tendons of extensor pollicis longus, extensor pollicis brevis and abductor pollicis longs define an area called the "anatomical snuffbox"
Elbow Articulation
The trochlea is oriented at an angle with the ulna when the elbow is extended creating a carrying angle.
The ulnar artery enters the hand lateral to the _____ nerve in the _____ ______.
The ulnar artery enters the hand lateral to the ulnar nerve in the ulnar canal. Divides into: 1. Superficial Palmar Arch 2. Deep palmar branch The superficial palmar arch gives rise to common palmar digital arteries for digits II-IV. The deep palmar branch of the ulnar artery contributes to the deep palmar arch.
What is the Tunnel of Guyon? What nerve and artery are present?
The ulnar nerve and artery lie outside the carpal tunnel within their own small ulnar tunnel (Tunnel of Guyon)...ulnar nerve and artery.
The ulnar nerver innvates all INTEROSSEI as well as ________? from what to what?
The ulnar nerve innervates all of the interossei as well as ½ the lumbricals (to ring and index digits).
Explain claw hand?
The unopposed extensor digitorum would thus be able to pull the MCP jts into hyperextension. Also, the patient would be unable to extend the IP jts when trying to straighten the fingers. The lesion would be most pronounced at the little and ring fingers since the lumbricals for the index and middle digits would be intact.
Thenar Compartment "OAF" Flexor Pollicis Brevis:
Thenar Compartment "OAF" Flexor Pollicis Brevis: superficial and deep heads P: (deep) capitate and trapezium D: proximal phalanx
Distal Attachments of rotator cuff muscles
Three rotator cuff muscles SIT on the greater tubercle of the humerus. The remaining rotator cuff muscle sits alone on the lesser tubercle (Subscapularis #4 P: subscapular fossa D: lesser tubercle)
What is the TFCC
Triangular fibrocartilage complex
True or False; Injury to the deep branch of the radial n. or its termination as the posterior interosseus nerve would not result in a loss of sensation.
True
true or false ulna never participates in wrist movement? Why
True...because of the TFCC
Ulnar N. (hand intrisics)
Ulnar N. = everthing else Hypothenar Compartment Plus: Palmaris Brevis Adductor pollicis Deep head of FPB ½ Lumbricals Dorsal/Ventral Interossei
The wrist joint has what joints?
Wrist Joint: (Condyloid Jt.) ● Ulnar collateral lig. between ulnar styloid process and triquetrum stabilize medially. ● Radial collateral lig. between radial styloid process and scaphoid stabilize laterally.
wrist joint is located where? ...specific crease
Wrist joint located at the proximal palmar crease.
brachial cutaneous n. = cutaneous n. of arm
brachial cutaneous n. = cutaneous n. of arm
Movements of thumb: Change planes and the CMC participates because it is a _____ joint...explain
saddle joint movement in two planes
Cubital Fossa
usually superficial to aponeurosis Cubital Fossa - transmits structures between the arm and forearm Superficially covered by cutaneous nerves and superficial veins. Later cutaneous n of forearm aka lateral ante brachial nerve is ALWAYS TAGGED.
What kind of joint is Intercarpal/Midcarpal Joints?
● Intercarpal/Midcarpal Joints (Plane Jts): Function is to augment movement at more proximal and distal joints.
Medial brachial cutaneous n. & Intercostal brachial cutaneous n.
● Medial brachial cutaneous n. (C8, T1) arises from the medial cord with the ulnar nerve and medial cutaneous nerve of the forearm. ● Intercostal brachial cutaneous n. (T2) arises from the second intercostal space and joins the medial brachial cutaneous n.
What divides arm into flexor (anterior) and extensor (posterior) compartments?
● The medial and lateral intermuscular septa attach to the supracondylar ridges of the humerus and divide the arm into anterior flexor and posterior extensor compartments. ● The arterial supply to the arm is provided by either the brachial artery or its primary branch, the deep (profunda) brachial artery.
