Cross Sectional Anatomy Chp 9 Upper Extremities

neurovasculature (upper extremities)

The ____________ of the upper extremity is composed primarily of the branches of the axillary and brachial arteries, their accompanying deep veins, a system of superficial veins, and the brachial plexus that innervates the upper extremity.

deep transverse metacarpal

- The ____ ___________ __________ ligament (DTML) consists of a series of short ligaments that connect the palmar plate of the metacarpal heads - The DTML prevents separation of the metacarpals. - (finger ligaments)

Hypothenar Group (hand muscles)

- Abductor digiti minimi muscle - Flexor digit minimi brevis muscle - Opponens digiti minimi muscle

Thenar Group (hand muscles)

- Abductor pollicis brevis muscle - Flexor pollicis brevis muscle - Adductor pollicis muscle - Opponens pollicis muscle

pronator teres

- All five of the superficial muscles in the ventral group have an origin from the common flexor tendon off the medial epicondyle of the humerus. The _________ ______ muscle has two heads of origin. - Its humeral head originates from the common flexor tendon, whereas the ulnar head originates near the coronoid process of the ulna. - The ________ ______ muscle courses obliquely before inserting on the lateral surface of the radius at midshaft. - It works in conjunction with the pronator quadratus muscle to pronate the forearm. (Ventral group) (SL)

Dorsal Group (Superficial Muscles)

- Brachioradialis - Extensor carpi radialis longus - Extensor carpi radialis brevis - Extensor digitorum - Extensor digitiminimi - Extensor carpi ulnaris

Muscles of the Scapula

- Deltoid - Teres major - Teres minor - Supraspinatus & Infraspinatus - Subscapularis

Ventral Group (Deep Muscles)

- Flexor digitorum profundus - Flexor pollicis longus - Pronator quadratus

ulnar tuberosity

- Immediately distal to the coronoid process is a roughened bony surface termed the ______ __________. -The tendon of the brachialis muscle inserts on both the coronoid process and the ______ ________. (proximal Ulna)

Metacarpal Group (hand muscle)

- Interossei muscle - Lumbricals muscle

teres minor

- Lying along the inferior border of the infraspinatus muscle is the elongated ______ ______ muscle, which also acts to laterally rotate the arm.

Joints (of the Hand)

- Metacarpophalangeal (MCP) - Proximal interphalangeal (PIP) - Distal interphalangeal (DIP) - The articulation of the phalanges of the second through fifth digits creates three interphalangeal joints: the metacarpophalangeal (MCP) joints classified as condyloid joints, proximal interphalangeal (PIP), and distal interphalangeal (DIP). - The proximal and distal interphalangeal joints are classified as hinge joints. - The first digit, which consists of two phalanges, has just two joints: the MCP joint, classified as a saddle joint, and an interphalangeal joint, classified as a hinge joint

Muscles (Connecting the Upper Extremity to the Anterior and Lateral Thoracic Walls)

- Pectoralis major - Pectoralis minor - Serratus anterior - Subclavius

Ventral Group (Superficial Muscles)

- Pronator teres - Flexor carpi radialis - Palmaris longus - Flexor carpi ulnaris - Flexor digitorum superficialis

phalanges

- The 14 __________ that make up the fingers, like the metacarpals, consist of a proximal (base), distal (head), and middle (body) portion. - Each digit consists of three _________ (proximal, middle, and distal), except for the thumb (first digit), which has only two _________ (proximal and distal).

Ligaments of the Fingers.

- The MCP and interphalangeal joints each have a palmar plate (ligament) and two collateral ligaments.

palmar plate (ligament)

- The ______ _______ (ligament) is a thick, dense fibrocartilaginous tissue that covers the palmar surface of the joints. - runs between and is connected to the collateral ligaments, creating the floor of the interphalangeal and MCP joints. - (finger ligaments)

palmar radiocarpal (arterial)

- The ______ ___________ arch or network is formed by the palmar carpal branches from the radial and ulnar arteries; the anterior interosseous artery, also a branch of the ulnar artery; and a recurrent branch from the deep palmar arch. - These vessels supply the carpal bones and joints. (wrist and hand)

Ulna (Proximal)

- The ______ is located medial within the forearm. - The proximal _____ consists of the olecranon and coronoid processes and the trochlear and radial notches. - The superficial dorsal surface is formed by the hook-shaped olecranon process, which is the attachment site for the triceps brachii muscle.

veins

- The ______ of the upper extremity are divided into deep and superficial groups. Numerous anastomoses occur between the groups. - The superficial venous system consists of extensive venous networks that are especially well developed within the upper extremity along with their accompanying arteries of the same name. - The deep ______ are often double and repeatedly anastomose with one another. - The ______ of the upper arm include the brachial, cephalic, and basilic. - The superficial ______ of the elbow include the cephalic, median cubital, basilic, and intermediate (median) antebrachial ________.

extensor carpi ulnaris

- The ________ _______ ________ muscle is a long, slender muscle that arises from the common extensor tendon and runs along the medial and dorsal side of the ulna to insert on the base of the fifth metacarpal. - Its main actions include extension of the hand at the wrist joint and adduction of the hand, resulting in ulnar deviation. (Dorsal grp) (SL)

trochlear notch

- The ________ ________ is a half-moon-shaped concave articular surface that curves around the trochlea of the humerus. - This articulation allows for flexion and extension of the elbow. - Located on the anterior portion of the distal end of the trochlear notch is a small beaklike process called the coronoid process. - Just distal and lateral to the coronoid process is a flattened depression called the radial notch, which is covered by articular cartilage for articulation with the radial head. (proximal Ulna)

serratus

- The _________ (sawlike) anterior muscle is visualized on the lateral border of the thorax. - It extends from the first through eighth or ninth ribs to the medial border of the scapula. - The primary action of the serratus anterior muscle is to protract and stabilize the scapula.

latissimus dorsi

- The _________ ______ muscle covers the inferior portion of the back as it extends from the spinous processes of the inferior six thoracic vertebrae, iliac crest, and inferior three or four ribs to the distal end of the intertubercular groove of the humerus. - medially rotates, extends, and adducts the humerus.

brachial artery

- The _________ ________ is the principal arterial supply to the arm. - It courses inferiorly on the medial side of the humerus and then continues anterior to the cubital fossa of the elbow. - is relatively superficial and palpable throughout its course. - It accompanies the median nerve, which crosses anterior to the artery in the middle of the arm. - During its course, the _______ ________ gives rise to numerous muscular branches, which include the profunda brachii, superior ulnar collateral, and inferior ulnar collateral arteries. (shoulder)

adductor pollicis

- The _________ _________ also has two heads: - The transverse head arises from the dorsal aspect of the third metacarpal, and the oblique head arises from numerous slips off the capitate, the bases of the second and third metacarpals, and the sheath of the flexor carpi radialis tendon. - The _________ _________ inserts onto the base of the first phalanx of the thumb to provide adduction and assist in the opposition and flexion of the thumb.

opponens pollicis

- The _________ _________ provides the main opposition for the thumb but also assists with adduction. - It arises from the trapezium and flexor retinaculum and inserts onto the radial aspect of the first metacarpal.

extensor retinaculum

- The _________ ______________ (dorsal carpal ligament), located dorsally, is much thinner. - It attaches medially to the ulnar styloid process, triquetrum, and pisiform, and laterally to the lateral margin of the radius. - Along its course, it forms six fibroosseous tunnels for the passage of the synovial sheaths containing the extensor tendons.

brachialis

- The _________ muscle originates from the anterior surface of the distal humerus and covers the anterior surface of the elbow joint before inserting on the ulnar tuberosity and the coronoid process. - considered to be the most important flexor muscle of the elbow joint. - Ventral group

pronator quadratus

- The __________ ____________, a quadrangular muscle, is the deepest muscle in the anterior aspect of the forearm. - It arises from the anterior and radial aspect of the distal ulna and passes transversely to insert on the anterior surface of the distal radius. - The deep fibers of this muscle help bind the radius and ulna together along with the interosseous membrane. - the prime mover in pronation of the forearm (Ventral grp) (DL)

subclavius

- The __________, a small triangular-shaped muscle that spans between the first rib and clavicle, acts to stabilize the clavicle and depress the shoulder.

carpometacarpal

- The _____________ joints are formed by the articulations between the carpus and the five metacarpals. - The carpometacarpal joint of the thumb is an independent joint formed by the articular surfaces of the trapezium and first metacarpal, creating a pure saddle joint. - The carpometacarpal articulations of the second to fifth digits are amphiarthrotic joints with little mobility. - The intermetacarpal joint exists between the bases of the metacarpals and is reinforced by the palmar and dorsal metacarpal ligaments

Radius (Distal)

- The broadened distal end of the ________ includes the cartilage-covered carpal articular surface, the ulnar notch, and the radial styloid process. - The carpal articular surface articulates with the scaphoid and lunate bones of the wrist. - The ulnar notch articulates with the ulna, and the styloid process serves as an attachment site for the extensor pollicis longus and extensor carpi radialis tendons. - The dorsal surface of the _________ contains several grooves that serve as passages for the extensor tendons. - Along with the grooves, a prominent ridge is located on the dorsal surface termed the radial dorsal tubercle, or Lister's tubercle, a common site for the formation of bony spurs.

extensor hood

- The dorsal surface of the hand and fingers contains the extensor mechanism or _________ _______. - The __________ ________ consists of the digital extensor tendon, extensor hood proper, and insertions of the lumbricals and interossei muscles and serves to maintain the integrity of the extensor tendons along the path of the MCP and interphalangeal joints. -(finger ligaments)

joint capsule

- The entire elbow joint is surrounded by a relatively loose _____ ________ that allows for the movements of flexion and extension. - weaker anteriorly and posteriorly but is reinforced medially and laterally by the strong radial and ulnar collateral ligaments.

venous system (of wrist and hand)

- The superficial ________ ______ forms a network at the dorsum of the hand termed the dorsal venous network (arch). - It is fed by the subcutaneous dorsal metacarpal veins of the fingers and continues to the distal forearm, where it drains into three major superficial veins: the cephalic, basilic, and intermediate (median) antebrachial veins of the forearm. - These large superficial veins anastomose frequently as they course superiorly. - The deep and superficial palmar venous arches of the hand empty into the radial and ulnar veins that then unite to form the brachial vein of the arm.

glenoid process

-The _______ ________, the largest of the projections, forms the lateral angle of the scapula and ends in a depression called the glenoid fossa (glenoid cavity). -There are two tubercles associated with the glenoid fossa, an upper supraglenoid tubercle and a lower infraglenoid tubercle, which serve as attachment sites for the long heads of the biceps brachii and triceps brachii muscles, respectively. -The shallow articular surface of the glenoid fossa joins with the relatively large articular surface of the humeral head to create the freely moving glenohumeral joint

scapular spine

-The _________ _________ arises from the upper third of the posterior surface of the scapula and extends obliquely and laterally to give rise to the acromion process. -A communication between the supraspinous and infraspinous fossae exists at the spinoglenoid notch, which is created where the acromion process and ________ _________ converge on the posterior aspect of the scapula.

transverse humeral ligament

-The _________ __________ ___________ is a broad band of connective tissue passing from the greater tubercle to the lesser tubercle of the humerus, forming a bridge over the intertubercular groove for protection of the long head of the biceps tendon

subacromial subdeltoid

-The ____________ __________ bursa is the main bursa of the shoulder and the largest bursa within the body. -Beginning at the coracoid process, the bursa extends laterally over the superior surface of the supraspinatus and infraspinatus tendons, extends beyond the acromion, and continues beneath the deltoid muscle to the greater tubercle of the humerus. -This bursa cushions the rotator cuff muscles and coracoacromial arch.

upper arm

-The muscles of the _______ _______ can be divided into ventral and dorsal groups according to their position. -The ventral group contains the - biceps brachii muscle - brachialis muscle - coracobrachialis muscle and the dorsal group consists of the - triceps brachii muscle - anconeus muscle.

glenoid labrum

-The outer rim of the glenoid fossa is surrounded by a fibrocartilaginous ring termed the _________ __________, which functions to deepen the articular surface of the glenoid fossa. -Superiorly, the ________ _______ blends with the tendon of the long head of the biceps brachii muscle. -In cross-section, it appears triangular. -The three glenohumeral ligaments (superior, middle, and inferior) thicken the fibrous capsule that surrounds the shoulder joint and contribute to the formation of the _______ _________. -They extend from the supraglenoid tubercle of the scapula to the lesser tubercle of the humerus.

fossa

-Two depressions located on the distal humerus are the anterior coronoid _______ and the deep posterior olecranon __________. -These depressions accommodate the coronoid and olecranon processes of the proximal ulna.

radial tuberosity

The _______ ___________ serves as the attachment point for the biceps brachii muscle (proximal radius)

pisiform

The ________ is considered a sesamoid bone that is embedded in the tendon of the flexor carpi ulnaris.

shoulder

The bony anatomy that comprises the __________ girdle includes the clavicle, scapula, and humerus

extensor digitiminimi

- The _______ __________ muscle arises from the common extensor tendon and passes under the extensor retinaculum in its own synovial compartment. - It then divides into two tendinous slips that insert on the proximal phalanx of the fifth digit to help with extension of the little finger. (Dorsal grp) (SL)

Dorsal Group (Deep Muscles)

- Abductor pollicis longus - Extensor pollicis brevis - Extensor pollicis longus - Extensor indicis - Supinator - The deep muscles of the _______ _______ consist of four extensors that act on either the first or second digit and include the supinator muscle. - The three deep extensors that act on the first digit are the abductor pollicis longus, extensor pollicis brevis, and the extensor pollicis longus muscles.

annular pulley

- Along the palmar surface of the fingers, the ligamentous structures of the radial and ulnar collateral ligaments, radial and ulnar accessory collateral ligaments, and palmar plates provide stability for the MCP and interphalangeal joints. - There is a fibroosseous tunnel along the palmar aspect of each finger for the passage of the flexor tendons. - The tunnel is created by well defined areas of thickening of the tendon sheath and is called the ______ _______ system. - It is composed of five _______ ________s and three cruciate pulleys, which are important structures that prevent the displacement of the tendons during flexion of the fingers. (finger ligaments)

interosseous membrane (Ulna)

- Another structure that is important in stabilizing and strengthening the connection between the radius and ulna is the _________ ________, a strong fibrous sheath stretching between the interosseous borders of both bones. (Distal Ulna)

extensor carpi radialis brevis

- The ______ _______ ________ _______ muscle has components that arise from the radial collateral and annular ligaments, as well as the common extensor tendon. - It runs along the dorsal surface of the wrist to insert at the base of the third metacarpal and acts to extend and abduct the hand at the wrist joint. (Dorsal grp) (SL)

metacarpals

- The five __________ are small tubular bones with a proximal end (base), distal end (head), and middle (body) portion.

deep palmar (arterial)

- The superficial palmar branch of the radial artery anastomoses with the superficial palmar branch of the ulnar artery to form the superficial palmar arch. - This arch gives rise to three common palmar digital arteries that anastomose with the palmar metacarpal arteries from the _______ ________ arch. - The deep palmar arch is formed by deep palmar branches of the radial and ulnar arteries and is located approximately 1 cm proximal to the superficial palmar arch. The deep palmar arch also gives rise to a recurrent branch that anastomoses with the palmar carpal branches of the radial and ulnar arteries. (wrist and hand)

rotator cuff

- The teres major muscle is a flat rectangular muscle that adducts and medially rotates the arm. - It extends from the inferior angle of the scapula to the medial aspect or lip of the intertubercular groove of the humerus. - The four remaining muscles, supraspinatus, infraspinatus, teres minor, and subscapularis, closely surround the scapula and constitute the ______ _______. - The _________ _______ provides dynamic stability to the shoulder joint and allows for adduction, abduction, and rotation of the humerus. - The supraspinatus, infraspinatus, and teres minor muscles are located on the posterior aspect of the scapula. - The tendons of these muscles insert on the greater tubercle of the humerus.

brachial

- The two deep__________ veins ascend the arm, one on either side of the brachial artery. - begin in the elbow from the union of the ulnar and radial veins and end in the axillary vein near the lower margin of the subscapularis muscle. - may join to form one brachial vein during part of their course. - The superficial veins of the upper arm include the cephalic and basilic. (shoulder vein)

bursa(e) (of elbow)

- There are two clinically important _______ located in the elbow: the olecranon _______ and the bicipitoradial ________. - The olecranon _______ is located within the subcutaneous tissue overlying the olecranon process. - The bicipitoradial _______ lies between the insertion of the biceps tendon and the radial tuberosity.

Distal Humerus

-The distal portion of the humerus has two distinct prominences termed the medial and lateral condyles, with associated epicondyles, which provide attachment sites for tendons and ligaments.

ulnar nerve

- At the elbow, the _______ _______ passes between the medial epicondyle of the humerus and the olecranon process within the cubital tunnel to enter the medial side of the flexor compartment of the forearm. - Posterior to the medial epicondyle, the ulnar nerve is superficial and easily palpable. - It supplies the flexor carpi ulnaris muscle and the medial side of the flexor digitorum profundus muscle in the forearm before entering the hand. - passes under the flexor retinaculum, along with the ulnar artery, to enter the palmar compartment of the hand. - At this point, the ulnar nerve divides into superficial and deep terminal branches that supply the ulnar flexors of the hand, as well as the skin on the medial side of the palm, medial half of the dorsum of the hand, fifth digit, and medial half of the fourth digit

opponens digiti minimi

- Like the flexor digiti minimi brevis muscle, the _________ ______ _____ arises from the hook of the hamate and the flexor retinaculum. - It inserts on the ulnar surface of the fifth metacarpal to bring the little finger into the position for opposition.

fat pads (of Elbow)

- Located within the olecranon and coronoid fossae are ____ ______ that fill the space between the synovial membrane and joint capsule. - The ____ ______ help cushion the area where the olecranon and coronoid processes move during flexion and extension of the elbow. (elbow)

extrinsic, intrinsic (ligaments of the wrist)

- Numerous _____(1)_____ and _____(2)_______ ligaments provide additional stability to the wrist. - The _____(1)_____ ligaments reinforce the joint cavity surrounding the carpal region and include palmar and dorsal radial carpal ligaments, the radial and ulnar collateral ligaments, and the TFCC. - The many articulations between the carpal bones are supported by the intercarpal ligaments or _____(2)_______ ligaments, which connect the carpal bones to each other. - The configuration of the _____(2)_______ ligaments, metacarpal ligaments, and the TFCC creates five different joint compartments that can be demonstrated by arthrography: (1) compartment of the first carpometacarpal articulation, (2) common carpometacarpal compartment, (3) midcarpal (mediocarpal) compartment, (4) intermetacarpal compartment, and (5) radiocarpal compartment.

radial collateral

- Reinforcing the lateral side (of elbow joint) is the triangular ______ (lateral) __________ ligament. - originates from the lateral epicondyle of the humerus, adjacent to and beneath the common extensor tendons, and spreads distally to insert on the annular ligament and the anterior and posterior margins of the radial notch of the ulna.

flexor digiti minimi brevis

- The _______ _____ _______ _______ muscle arises from the flexor retinaculum and the hook of the hamate. - It fuses with the tendon of the abductor digiti minimi to insert on the base of the first phalanx of the fifth digit. - It flexes at the MCP joint.

lumbrical (hand muslce)

- The four small __________ muscles arise from the tendons of the flexor digitorum profundus and pass to the radial side of the corresponding finger to insert on the extensor expansion covering the dorsal surface of the finger. - The __________ flex the first phalanges at the MCP joints and extend the second and third phalanges at the interphalangeal joints.

deltoid

- The large ________ muscle originates on the clavicle, acromion, and scapular spine to blanket the shoulder joint as it extends to insert on the ________ tuberosity of the humerus. -This powerful muscle forms the rounded contour of the shoulder and functions primarily to abduct the arm.

Muscles (Connecting the Upper Extremity to the Vertebral Column)

- Trapezius - Levator scapulae - Latissimus dorsi - Rhomboid major - Rhomboid minor

coracoid process

-Located on the anterolateral surface of the scapula is a beak like process termed the ________ _________, which arises just medial to the glenoid process and functions to protect the shoulder joint, which lies beneath it. -The _________ _________ is an attachment site for the pectoralis minor, the short head of the biceps brachii, and the coracobrachialis muscles. -The scapular notch is located just medial to the __________ __________ on the superior margin of the scapula and allows for the passage of the suprascapular nerve.

muscles

-Numerous __________ and their tendons provide stability for the shoulder joint and movement of the upper arm. -These can be separated into four muscle groups: (1) muscles that connect the upper extremity to the vertebral column (2) muscles of the scapula (3) muscles that connect the upper extremity to the anterior thoracic wall (4) muscles of the upper arm.

biceps brachii

-The _________ _________muscle is located on the anterior surface of the humerus and acts as a strong flexor of the forearm. - The biceps brachii muscle is named "biceps" because of its two expanded heads of proximal attachment (long and short). - The tendon of the long head arises from the supraglenoid tubercle and courses through the intertubercular (bicipital) groove to merge with the tendon from the short head. - The short head of the ________ ________muscle originates from the coracoid process and joins with the long head to create the ________ ________ muscle, which terminates in two tendons. - The stronger tendon inserts on the radial tuberosity, and the other tendon creates the bicipital aponeurosis, which radiates into the fascia of the forearm. - Ventral group

Bursae

-The tendons and ligaments of the shoulder joint are cushioned by several fluid-filled ___________. -_________, within the shoulder, reduce friction where large muscles and tendons pass across the joint capsule. -Two prominent shoulder ________ include the subacromial-subdeltoid and subscapular bursae.

Muscles of the Forearm

- One method to classify the ________ ___ ____ __________ is to use the radius, ulna, and interosseous membrane to divide them into a ventral group (the flexors) and a dorsal group (the extensors). - The two groups can be further divided into superficial and deep muscles. -Ventral Group Superficial Muscles - Pronator teres - Flexor carpi radialis - Palmaris longus - Flexor carpi ulnaris - Flexor digitorum superficialis - Ventral Group—Deep Muscles - Flexor digitorum profundus - Flexor pollicis longus - Pronator quadratus - Dorsal Group—Superficial Muscles - Brachioradialis - Extensor carpi radialis longus - Extensor carpi radialis brevis - Extensor digitorum - Extensor digitiminimi - Extensor carpi ulnaris - Dorsal Group—Deep Muscles - Abductor pollicis longus - Extensor pollicis brevis - Extensor pollicis longus - Extensor indicis Supinator

Ulna (Distal)

- The smaller, distal end of the _____ has two prominent projections. - The larger, rounded projection is an articular eminence termed the head of the_____. - It articulates with the ulnar notch of the radius and the triangular fibrocartilage complex. - The small conical projection on the medial surface is called the ulnar styloid process, which serves as the attachment site for the ulnar collateral ligament of the wrist.

Ligament(s) (elbow)

- The stability of the elbow joint primarily depends on the collateral ___________, which are woven into the lateral portions of the joint capsule. - ulnar (medial) collateral __________ (anterior, posterior and transverse band) - radial (lateral) collateral __________ - annular ___________

clavicle

-The ___________ connects the upper limb to the trunk of the body and provides attachments for several muscles and ligaments. -It is a long, slender bone located anteriorly that extends transversely from the sternum to the acromion process of the scapula. -The widened sternal end of the __________ articulates with the manubrium of the sternum to form the sternoclavicular (SC) joint, and its flattened acromial end articulates with the acromion process of the scapula to form the acromioclavicu lar (AC) joint. -The medial two-thirds of the body of the __________ is anteriorly convex, whereas the lateral one- third is flattened and anteriorly concave.

subscapular

-The ____________ bursa is located between the subscapularis tendon and the scapula and communicates with the synovial cavity through an opening in the joint capsule. -This bursa protects the subscapularis tendon, where it passes inferior to the coracoid process and over the neck of the scapula

coracoacromial ligament

-The _______________ ________ is another important ligament located on the anterior portion of the shoulder. -As this ligament joins the coracoid process and acromion, it forms a strong bridge, termed the coracoacromial arch, which protects the humeral head and rotator cuff tendons from direct trauma and prevents displacement of the humeral head superiorly.

capitellum (1), trochlea (2)

-The distal humerus has two cartilage-covered articular surfaces—the ____(1)______ and the ____(2)_____ —for articulation with the radius and ulna. -The lateral of the two surfaces is the ____(1)______, a rounded projection that articulates with the concave surface of the radial head. -The ____(2)_______ is more medial and has the appearance of an hourglass if viewed in the horizontal plane. -The shape of the ____(2)______ helps keep the ulna in position during flexion between the humerus and radius

Muscles (1) and Tendons (2) (of forearm and wrist)

-The numerous _____(1)_____ of the forearm become tendinous just before the wrist joint. - The many ______(2)______ located in the wrist can be divided into flexor (palmar) and extensor (dorsal) tendon groups. - The flexor tendon group collectively flexes the fingers and wrist. - As this group courses through the carpal tunnel, the tendons appear to be arranged in two discrete rows. - The tendons of the extensor group span the superficial surface of the wrist to extend the fingers and wrist

medial epicondyle

The ________ _________ serves as the site of origin for the common flexor tendon, pronator teres muscle, and medial collateral ligament, whereas the lateral epicondyle serves as the attachment site for the common extensor tendon, supinator muscle, and lateral collateral ligament. Just lateral to the __________ ___________, along its posterior surface, is a shallow groove containing the ulnar nerve.

coracohumeral ligament

The _____________ __________ passes from the lateral side of the coracoid process of the scapula to the greater tubercle of the humerus.

coracoclavicular ligaments

The _____________ ____________ help to maintain the position of the clavicle, in relation to the acromion, by spanning the distance between the clavicle and coracoid process of the scapula.

infraspinatus

The _____________ muscle is a triangular muscle that lies below the scapular spine in the infraspinous fossa. It acts to laterally rotate the arm.

acromioclavicular ligament

The ______________ ____________, at the acromioclavicular joint, provides support for the superior surface of the shoulder.

flexor carpi ulnaris

- The _____ ______ _______ muscle is the most medial of the superficial muscles located in the anterior portion of the forearm. - It has two heads: The humeral head originates from the common flexor tendon, and the ulnar head originates from the olecranon process. - It inserts onto the pisiform, hook of the hamate, and fifth metacarpal and acts to flex and adduct (ulnar deviation) the hand at the wrist joint. (Ventral grp) (SL)

articular joint capsule (OF SHOULDER)

-The __________ ________ __________ completely encloses the shoulder joint and is quite thin and loose to allow for extreme freedom of movement. -When the arm is adducted, the capsule sags to form a pouchlike area termed the axillary recess. -The capsule is attached medially to the glenoid fossa of the scapula and laterally to the anatomic neck of the humerus. -It is strengthened by several muscles and ligaments, including the rotator cuff muscles and the long head of the biceps brachii muscle, as well as the glenohumeral and coracohumeral ligaments. -There are two openings of the joint capsule. -The first is to allow for the passage of the long head of the biceps brachii, and the second establishes a communication between the joint and the subscapularis bursa. -A synovial membrane lines the fibrous capsule and extends to the glenoid labrum and neck of the humerus. -The synovial membrane provides a sheath for the tendon of the long head of the biceps brachii muscle, where it passes into the joint cavity through the intertubercular groove, extending as far as the surgical neck of the humerus.

scapula

-The ___________ is a triangular-shaped flat bone that forms the posterior portion of the shoulder girdle. -It has a medial margin (vertebral border), a lateral margin (axillary border), and a superior margin. -The margins are separated by the superior, inferior, and lateral angles. -The anterior surface of the _________, the subscapular fossa, is flat and slightly concave. -The posterior surface of the _________ is divided by the scapular spine into a smaller supraspinous fossa and a larger infra spinous fossa. -Four projections of the ________ provide attachment sites for the muscles and ligaments contributing to the shoulder girdle. -These include the scapular spine, acromion process, coracoid process, and glenoid process.

axillary

- The large ________ vein lies on the medial side of the axillary artery. - It extends from the lower border of the teres major muscle to the lateral surface of the first rib to continue as the subclavian vein. - receives tributaries that correspond to the branches of the axillary artery.

Ligaments of the shoulder

- The three glenohumeral ligaments - coracohumeral ligament - coraco acromial ligament - coracoclavicular ligaments - acromioclavicular ligament - transverse humeral ligament

trapezius

- The large triangular ___________ muscle covers the posterior aspect of the neck and superior half of the back. - It connects the upper limb to the cranium via the external occipital protuberance and to the vertebral column via the ligamentum nuchae and spinous processes of C7-T12. - It inserts on the clavicle, acromion process, and scapular spine. - functions to stabilize the scapula, as well as to elevate, retract, and depress the scapula.

abductor pollicis longus

- The long, slender ________ ________ ________ muscle arises from the dorsal surfaces of the ulna and radius and from the interosseous membrane. - It inserts at the base of the first metacarpal to abduct and extend the thumb. (Dorsal grp) (DL)

Muscles of the Hand

- The muscles of the hand can be divided into three groups: (1) metacarpal group (muscles of the metacarpals are considered to be the central muscles of the hand) (2) thenar group (muscles involving the thumb and creating the thenar eminence on the radial side) (3) hypothenar group (muscles involving the fifth digit and creating the hypothenar eminence on the ulnar side)

ulnar artery

- The _____ __________ also gives rise to several branches that supply the elbow and forearm. - The first branch of the _______ ________ is the anterior ulnar recurrent artery, which supplies the brachialis and pronator teres muscles. - It courses just anterior to the medial condyle of the humerus to anastomose with the inferior ulnar collateral branch of the brachial artery. - The posterior ulnar recurrent artery courses behind the medial epicondyle of the humerus to anastomose with the superior ulnar collateral branch of the brachial artery. - It supplies the flexor carpi ulnaris, pronator teres, and anconeus muscles. - The common interosseous artery branches from the ______ ______ and almost immediately bifurcates into the anterior and posterior interosseous arteries. - These arteries and their branches supply the median nerve, deep flexor and extensor muscles of the forearm, superficial extensor muscles of the forearm, and radius and ulna. (elbow)

ulnar collateral

- The ______ (medial) _________ ligament consists of three components: an anterior band, a posterior band, and a transverse band (ligament of Cooper). - The anterior band, which is the strongest, extends from the medial epicondyle of the humerus to the medial aspect of the coronoid process. - The posterior band originates along with the anterior band from the medial epicondyle of the humerus and inserts on the medial aspect of the olecranon process, forming a triangular plate. - The weaker transverse band stretches between the medial surfaces of the coronoid and olecranon processes to unite the anterior and posterior bands. - The _____ __________ ligament forms the floor of the cubital tunnel for passage of the ulnar nerve.

extensor carpi radialis longus

- The ______ ______ _____ _______ muscle arises just distal to the brachioradialis muscle on the lower third of the supracondylar ridge of the humerus. - It runs posterior and deep to the brachioradialis to insert on the base of the second metacarpal. - It acts as an extensor and abductor of the hand at the wrist joint. - The other superficial muscles (extensor carpi radialis brevis, extensor digitorum, extensor digitiminimi, extensor carpi ulnaris) arise from a common extensor tendon attached to the lateral epicondyle of the humerus. - At the level of the elbow they appear as one structure but become more distinct distally as they insert on various structures about the wrist and hand. (Dorsal grp) (SL)

flexor digitorum profundus

- The ______ _______ __________ muscle is a long, thick muscle responsible for flexing the distal interphalangeal joints of the fingers. - It originates from the anterior surface of the proximal ulna and extends medially to the interosseous membrane. - Similar to the flexor digitorum superficialis muscle, the ______ __________ ___________ divides into four tendons before reaching the flexor retinaculum. - The four tendons pass deep in the carpal tunnel and continue distally to insert on the distal phalanges, where they pair up with the flexor digitorum superficialis tendons to provide flexion of the middle and proximal phalanges of the second through fifth digits. (Ventral grp) (DL)

flexor digitorum superficialis

- The ______ _______ ___________ muscle is the largest muscle of the superficial muscles in the forearm. - It arises from three heads: the humeral head from the common flexor tendon, the ulnar head from the coronoid process, and the radial head from the anterior surface of the proximal half of the radius. - Just before reaching the flexor retinaculum, the muscle divides into four tendons that share a common synovial sheath through the carpal tunnel. - After passing under the flexor retinaculum, the tendons insert on the lateral sides of the middle phalanges of the second to fifth digits. - a strong flexor of the middle and proximal phalanges of the second through fifth digits (Ventral grp) (SL)

carpal bones

- The ______ _______ are arranged in proximal and distal rows. - Located in the proximal row of carpal bones are the scaphoid (navicular), lunate (semilunar), triquetral (triquetrum), and pisiform bones. - The distal row consists of the trapezium (greater multangular), trapezoid (lesser multangular), capitate (os magnum), and hamate (unciform) bones.

flexor pollicis longus

- The ______ ________ ________ muscle arises from the anterior surface of the radius and adjacent interosseous membrane and runs lateral to the flexor digitorum profundus to cover the anterior aspect of the radius. - After passing through the carpal tunnel, the _______ ________ ________ tendon runs between the flexor pollicis brevis and adductor pollicis brevis muscles to insert at the base of the first distal phalanx to provide flexion to the thumb. (Ventral grp) (DL)

dorsal radiocarpal (arterial)

- The ______ _________ arch or network is formed by dorsal carpal branches of the radial and ulnar arteries. - The dorsal carpal arch also receives contributions from the anterior and posterior interosseous arteries. - The arch lies close to the dorsal surface of the carpals and gives rise to three dorsal metacarpal arteries and branches that supply the distal regions of the ulna and radius, carpal bones, and intercarpal joints. (wrist and hand)

distal radioulnar

- The ______ __________ joint is created when the ulnar notch of the radius moves around the articular circumference of the ulna, providing the movements of supination and pronation. - The main stabilizing element of the DRUJ is an articular disk called the triangular fibro cartilage complex (TFCC). - The TFCC is a fan-shaped band of fibrous tissue that originates on the medial surface of the distal radius and traverses horizontally to insert on the ulnar styloid process. - It rotates against the distal surface of the ulnar head during pronation and supination and separates the ulna from the carpal bones. - The proximal surface of the radiocarpal articulation is formed by the articular carpal surface of the radius and the TFCC, whereas the distal surface is formed by the articular surfaces of the scaphoid, lunate, and triquetrum and the interosseous ligaments connecting them. - The midcarpal joint is formed by the articulations between the proximal and distal carpal rows. - The articulation between the carpals within each row creates the intercarpal joints.

joints (wrist and hand)

- The ______ of the wrist and hand are quite complex and consist of the following: - distal radioulnar articulation - radiocarpal articulation (proximal joint of hand) - midcarpal articulation (distal joint of hand) - intercarpal articulations (articulations between proximal and distal carpals) - carpometacarpal articulations (between carpals and metacarpals) - intermetacarpal articulations (between bases of metacarpals two through five) - interphalangeal joints (between phalanges of each digit) (hand joint)

abductor, flexor

- The ______(1)______ pollicis brevis is a thin, flat superficial muscle arising from the transverse carpal ligament, navicular, and trapezium. - It runs inferiorly and laterally to insert on the base of the first phalanx of the thumb to abduct the thumb. - The _____(2)______ pollicis brevis has two heads: - The superficial or lateral head arises from the flexor retinaculum, and the deep or medial head arises from the trapezium, trapezoid, and capitate. - This muscle inserts on the radial and ulnar base of the first phalanx to flex, adduct, and abduct the thumb. - Frequently, a sesamoid bone can be found in the insertion tendon on the radial side.

flexor carpi radialis

- The _______ ______ ________ muscle originates from the common flexor tendon and is located medial to the pronator teres. - Its tendon passes through the carpal tunnel of the flexor retinaculum before inserting on the palmar surface of the base of the second metacarpal. - Its actions include flexion and radial deviation of the hand at the wrist joint. (ventral group) (SL)

triceps brachii

- The _______ _______ muscle is located on the posterior surface of the humerus and is the main extensor of the forearm. - It is named triceps because of its three heads of proximal attachment (long, medial, and lateral). - The long head of the triceps originates from the infraglenoid tubercle of the scapula, the medial head originates from the entire dorsal surface of the humerus distal to the radial groove, and the lateral head arises from the dorsal surface and lateral intermuscular septum of the humerus. - All three heads join in a common tendon that inserts on the olecranon process of the ulna and the posterior joint capsule. - Dorsal group

carpal tunnel

- The _______ ________ is created by the concave arrangement of the carpal bones. - A thick ligamentous band called the flexor retinaculum (transverse carpal ligament) stretches across the carpal tunnel to create an enclosure for the passage of tendons and the median nerve. - The flexor retinaculum inserts medially on the pisiform and hook of the hamate and spans the wrist to insert laterally on the scaphoid and trapezium. - In addition to the _______ ________, another tunnel called Guyon canal is formed where the ulnar extension of the flexor retinaculum continues over the pisiform and hamate. - This creates a potential site for compression of the ulnar nerve.

extensor digitorum

- The _______ __________ muscle is the main extensor of the second to fifth digits and occupies much of the posterior surface of the forearm. - It arises from the common extensor tendon and divides into four individual tendinous slips just proximal to the wrist. - The four tendons run in a single synovial sheath as they pass under the extensor retinaculum. - The tendons insert into the extensor expansions of the second through fifth digits, helping to form the extensor hoods. - In addition, small slips of the tendon spread out and run to the bases of the proximal phalanges and to the capsules of the metacarpophalangeal joints. - The _________ __________ muscle extends and spreads the fingers and extends the hand at the wrist joint. (Dorsal grp) (SL)

abductor digiti minimi

- The ________ ______ ________ muscle arises from the pisiform and the flexor retinaculum to end in a flat tendon that inserts onto the ulnar base of the first phalanx of the little finger. - the main abductor of the little finger.

extensor pollicis longus

- The ________ _______ _______ muscle arises from the dorsal surface of the ulna and interosseous membrane just distal to the abductor pollicis longus muscle. - After passing through the extensor retinaculum, it crosses over the extensor carpi radialis longus and brevis muscles to insert at the base of the distal phalanx of the first digit. - Its main action is to extend the distal phalanx of the first digit, but it can also abduct the hand. - (Dorsal grp) (DL)

radial nerve

- The ________ _______ is the largest branch of the brachial plexus. - It passes inferolaterally around the body of the humerus in the radial groove. - It continues inferiorly between the brachialis and brachioradialis muscles to the level of the lateral epicondyle of the humerus, where it divides into deep and superficial branches. - The deep branches supply all the extensors in the arm and forearm, and the cutaneous branches innervate the skin on the dorsal side of the arm and hand. - The superficial branch, the direct continuation of the radial nerve, is entirely sensory. - It supplies the skin and fascia over the lateral two-thirds of the dorsum of the hand, the dorsum of the thumb, and the proximal parts of the lateral three and a half digits on their dorsal surfaces.

axillary artery

- The ________ ________ begins at the lateral border of the first rib as a continuation of the subclavian artery. - It ends at the inferior border of the teres major muscle, where it passes into the arm and becomes the brachial artery. - The _______ _______ and its branches supply blood to numerous thoracic and shoulder structures, including the first and second intercostal spaces; the axillary lymph nodes; the mammary gland in women; and the scapular, serratus anterior, pectoral, latissimus dorsi, deltoid, and triceps brachii muscles. - The branches of the ______ _______ typically include the superior thoracic, thoracoacromial, lateral thoracic, subscapular, and anterior and posterior humeral circumflex arteries. (shoulder)

palmaris longus

- The ________ _________ muscle originates from the common flexor tendon and passes superficial to the flexor retinaculum to merge with the palmar aponeurosis. - It acts to flex the hand and tighten the palmar aponeurosis.

terminal branches

- The ________ _________ of the radial and ulnar arteries form the palmar arches of the wrist and hand. - These arches emit branches that serve the wrist, palm, and digits.

elbow

- The ________ is a complex hinge-pivot joint created by the articulations of the humerus, radius, and ulna. - All three articulations communicate with each other within a single joint capsule. - The radius and ulna are the bones of the forearm, with the radius located on the lateral side. - The radioulnar and radiohumeral articulations create the pivot joint that aids in supination and pronation of the elbow. - The radiohumeral and ulnohumeral articulations form the hinge joint that allows for flexion and extension

Radius (Proximal)

- The ________ is a long, slender bone with a proximal portion that consists of the radial head, neck, and tuberosity. - The radial head has a flat cartilage- covered depression or fossa (fovea of the radius) that articulates with the capitellum of the humerus. - In addition, the articular circumference of the radial head articulates against the radial notch of the ulna during supination and pronation. -The radial head is attached to the body of the ________ by the narrow radial neck. -Located at the distal portion of the neck on the medial side of the radius is a roughened projection termed the radial tuberosity.

annular

- The ________ ligament forms a fibrous ring that encircles the radial head and attaches to the anterior and posterior margins of the radial notch. - It also has a narrow portion that tightens around the radial neck to prevent inferior displacement of the radius. - considered a key structure in the proximal radioulnar joint, allowing the head of the radius to rotate freely.

median

- The ________ nerve descends the cubital fossa deep to the _______ cubital vein. - It supplies the pronator teres muscle of the arm and all the superficial and deep flexor muscles of the forearm, except the flexor carpi ulnaris muscle. - It gives off an anterior interosseous branch that descends within the forearm to supply the flexor digitorum profundus muscle. - The ________ nerve courses through the carpal tunnel of the wrist, typically superficial to the flexor tendons. - It supplies the flexors of the hand, the skin of the wrist, the thenar eminence, the palm of the hand, and the sides of the first three digits and the lateral half of the fourth.

extensor indicis

- The _________ _________ muscle arises from the distal third of the dorsal ulna and the interosseous membrane and runs with the extensor digitorum muscle through the extensor retinaculum to insert on the dorsal aponeurosis of the second digit. - It functions with the extensor digitorum muscle to extend the index finger, as if pointing. (dorsal grp) (DL)

levator scapulae

- The _________ _________ muscle lies deep in the neck and functions to elevate and rotate the scapula. - It extends from the transverse processes of C1-C4 to the superior angle and medial border of the scapula above its spine

brachial plexus

- The _________ __________, is a large network of nerves that innervate the upper limb. - It extends from the neck into the axilla. - formed by the union of the ventral rami of nerves C5-C8 and the greater part of the T1 ventral ramus. - The ventral rami from C5 and C6 unite to form a superior trunk, the ventral ramus of C7 continues as the middle trunk, and the ventral rami of C8 and T1 unite to form an inferior trunk. - Each of these trunks divides into an anterior and posterior division. - The anterior divisions supply the anterior (flexor) parts of the upper limb, and the posterior divisions supply the posterior (extensor) parts of the upper limb. - These divisions form three cords (posterior, lateral, and medial), which continue to divide to form the median, ulnar, musculocutaneous, and radial nerves. - These nerves supply the muscles of the forearm and hand.

supinator

- The __________ muscle originates from two heads: oblique and transverse. - The oblique head originates from the lateral epicondyle and collateral ligament, whereas the transverse head originates from the _________ crest of the ulna. - Both heads wrap laterally around the proximal radius to insert on the posterolateral and anterior surfaces of the proximal radius to supinate the forearm. (dorsal grp) (DL)

pectoralis

- The __________ muscles (major and minor), located on the anterior surface of the chest, primarily aid in the movement of the upper limb. - The large fan-shaped ________ major muscle, which has two heads, covers the superior part of the thorax. - It spans from the sternum (sternal head), clavicle (clavicular head), cartilaginous attachments of the upper six ribs, and the aponeurosis of the external oblique muscle to the lateral aspect or lip of the intertubercular groove of the humerus. - Its primary functions are to adduct, medially rotate, flex, and extend the humerus and to assist in forced inspiration. - The smaller triangular-shaped _________ minor muscle lies beneath the ________ major muscle and acts to depress the scapula and assist the serratus anterior muscle in pulling the scapula forward. - It extends from the coracoid process to the anterior surface of the third to fifth ribs.

rhomboid

- The __________ muscles, major and minor, lie deep to the trapezius muscle. - The rhomboid major is wider than the rhomboid minor. - They parallel each other as they span from the ligamentum nuchae and spinous processes of C7-T5 to the medial border of the scapula. - They function to retract the scapula and fix the scapula to the thoracic wall -Minor- C7- T1 - Major- T2- T5

cephalic

- The __________ vein courses from the radial side of the dorsal venous arch of the hand and then ascends to the midpoint of the forearm, where it curves around to the ventral surface of the forearm and ascends the lateral aspect of the upper arm, along the anterolateral border of the biceps brachii muscle, to open into the axillary vein, just below the clavicle. - It drains the superficial parts of the lateral hand and lateral forearm. - The cephalic vein courses along the radial side of the elbow and may give rise to the median cubital vein, which ascends in an oblique and medial course to create an anastomosis between the basilic and cephalic veins. - The median cubital vein is a common site for venipuncture.

brachioradialis

- The ____________ is an extensor muscle lying along the lateral border of the forearm. - This large muscle arises from the upper two-thirds of the supracondylar ridge of the humerus and attaches distally to the radial styloid process. - flexes the forearm at the elbow and assists with pronation and supination. (Dorsal grp) (SL)

subscapularis

- The ______________ muscle is the only muscle of the rotator cuff located on the anterior surface of the scapula; - its tendon inserts on the lesser tubercle of the humerus. - acts to medially rotate the humerus

supraspinatus

- The ______________ muscle lies in the supraspinous fossa of the scapula and helps abduct the arm. - - The tendon of the supraspinatus muscle is the most frequently injured tendon of the rotator cuff because of possible impingement as it extends under the acromioclavicular joint and continues over the humeral head.

musculocutaneous nerve

- The _________________ _______ descends to the lateral side of the arm and elbow to innervate the flexors in the arm and the skin of the forearm, wrist, and thenar region of the hand. - It emits branches that supply both heads of the biceps brachii muscle, the brachialis muscle, and the elbow joint. It innervates the skin of the dorsal surface of the arm. - A continuation of the ___________________ _______ is the lateral cutaneous nerve, which terminates into cutaneous branches that supply the skin covering the radial side of the wrist and the thenar eminence.

coracobrachialis

- The ___________________ muscle is a long, narrow muscle located in the superomedial aspect of the arm. - It arises from the coracoid process along with the short head of the biceps brachii and extends to insert on the medial surface of the humerus. - The primary action is to assist with flexion and adduction of the arm, but it also helps hold the head of the humerus within the joint capsule - Ventral group

antebrachial

- The basilic vein courses along the posteromedial aspect of the forearm, crosses the elbow, then takes a deep course in the axilla to join the brachial vein. - The intermediate (median) ___________ vein transports blood from the superficial palmar venous arch and anterior forearm. - It ascends the ventral side of the forearm on the ulnar side and typically ends in the basilic vein.

wrist and hand

- The bony anatomy of the _____ _____ ______ consists of: - the distal radius and ulna - 8 carpal bones - 5 metacarpals - 14 phalanges. - Both the distal radius and ulna have a conical styloid process that acts as an attachment site for ligaments. - The radial styloid process is located on the lateral surface of the radius, whereas the ulnar styloid process is located on the posteromedial side of the ulna.

radial artery

- The brachial artery divides at the cubital fossa into the radial and ulnar arteries. (elbow) - The ______ _______ begins at the level of the head of the radius within the anterior compartment of the forearm. - It courses beneath the brachioradialis muscle and then continues its course just deep to the skin, along the lateral side of the anterior forearm to the wrist. - It passes anterior to the radial styloid process to enter the hand. - The most proximal branch of the ________ _______ is the radial recurrent artery, which supplies the brachioradialis, supinator, and brachialis muscles and the elbow joint. - Within the forearm, the _______ _________ gives off several direct muscular branches.

extensor pollicis brevis

- The short ______ ______ _______ muscle arises from the dorsal surfaces of the ulna and radius and from the interosseous membrane just distal to the abductor pollicis longus muscle. - It inserts at the base of the proximal phalanx of the first digit and works together with the abductor pollicis longus muscle to extend and abduct the thumb. (Dorsal grp) (DL)

anconeus

- The small, triangular ___________ muscle originates on the lateral epicondyle of the humerus and crosses obliquely to insert on the dorsal surface of the olecranon process, close to the tendon of the triceps brachii. - It assists the triceps brachii in extension and also provides dynamic joint stability to the lateral joint capsule. - Dorsal group

interossei (hand muscle)

- There are seven short ____________ muscles in the metacarpal muscle group: - 3 single-headed muscles located on the palmar surface and four double-headed muscles located on the dorsal surface. - The three palmar ___________ muscles arise from the second, fourth, and fifth metacarpals and insert on the corresponding proximal phalanges, frequently radiating into the corresponding tendons of the dorsal aponeurosis. - These muscles are responsible for flexion at the MCP joints and extension at the interphalangeal joints. - The dorsal ____________ arise from two heads on the sides of the five metacarpal bones to insert on the proximal phalanges and radiate onto the dorsal aponeurosis. -Like their palmar counterparts, the dorsal ____________ flex at the MCP joints and extend at the interphalangeal joints.

humerus

-The _________ is a long bone that articulates with the scapula superiorly and the radius and ulna inferiorly. -It consists of a proximal end, a body (shaft), and a distal end. -The proximal end is formed by the head of the humerus. -Two tubercles project from the humeral head to provide attachment sites for tendons and ligaments. -The lesser tubercle is located on the anterior surface of the humeral head, whereas the greater tubercle is located on the lateral surface of the humeral head. -The tubercles are separated by the intertubercular (bicipital) groove. -The humerus has two necks, the more proximal anatomic neck and the surgical neck, located inferior to the tubercles just distal to the humeral head. -In the middle of the body or shaft of the humerus, on the anterior surface, is the roughened area of the deltoid tuberosity, which provides attachment for the deltoid muscle