elbow & forearm

the extensors of the elbow

- anconeus - triceps brachii

roles of the anconeus

- assists triceps in extending elbow joint - synergist to pronation & supination to keep the elbow stable

the muscles of supination

- biceps brachii - supinator

the 4 muscles innervated by the radial nerve

- brachioradialis - anconeus - triceps brachii - extensor carpi radialis

wrist extensors

- extensor carpi radialis longus - extensor carpi radialis brevis - extensor carpi ulnaris

wrist flexors

- flexor carpi radialis - flexor carpi ulnaris - palmaris longus

muscles of pronation

- pronator teres - pronator quadratus

muscles that act on the radialulnar joints

- pronators (pronator teres & quadratus) - supinators (biceps brachii & supinator)

ROM in elbow depends on

- type of motion: more PROM than AROM - position of forearm: more flexion in supination - position of shoulder

normal carrying angle

10 - 15 d. for men, 15 for women (slightly higher for women)

there are __ bursae in the elbow

7 (between tendon of triceps & olecranon, between muscles, between bones & skin)

maximum torque is generated at

90 d. of flexion (mid position)

innervated by radial nerve mnemonic

BATE (brachioradialis, anconeus, triceps brachii, extensor carpi radialis)

the flexors of the elbow

BBBP biceps brachii brachialis brachioradialis pronator teres

the ___ ligament wraps around the head of the radius (radial notch)

annular

the wrist flexors are on the ___ of the forearm

anterior

the medial & lateral cords are in

anterior division of the anterior compartment

nerves from the anterior divisions feed

anterior muscles - flexors

the fibrous joint capsule is fairly loose and weakest ____ & __, but well supported ___ & ___

anteriorly, posteriorly; laterally, medially

during flexion, the humerus & forearm

are in alignment, so you can't see the carrying angle

both articulating surfaces of the humeralulnar joint are covered in

articular cartilage

the posterior division leads to the posterior cord which leads to these nerves

axillary & radial

only the ___ can become actively insufficient (because it acts on 3 joints)

biceps brachii

the radial tuberosity is the attachment site for the

biceps brachii

if shoulder is hyperextended, the ____ will become ____ insufficient to prevent elbow extension

biceps, passively insufficient

the head of the radius articulates with the

capitulum

the humeralradial joint (hinge) is where the

capitulum of the humerus meets the radial notch of the radius

the humeralradial joint is where the

capitulum of the humerus meets the radial notch of the radius

the head of the ulna articulates with the

carpals of wrist

the lateral deviation of the forearm due to the slight medial tilt of the angled trochlea & trochlear notch results in the

carrying angle (valgus aka pointed inwardly)

the distal attachment of the triceps brachii attaches to the ____ ___, which attaches to the ___ of the ___

common tendon; olecranon of ulna

the coracobrachialis attaches to the

coracoid process of the scapula

the coronoid process of the ulna slides into the

coronoid fossa

flexion is limited by

coronoid process hitting on the coronoid fossa (soft end feel)

innervated by musculocutaneous nerve

elbow flexors except brachoradialis (innervated by radial nerve) BBC - biceps brachii - brachialis - coracobrachialis

brachioradialis flexes the ___ ___ and is strongest in ___ - ____

elbow joint, mid-position

the humeralulnar & humeralradial joints (elbow) and proximal radialulnar joint are enclosed in the same

fibrous joint capsule

the radial head & radial fossa of the humerus contact during

flexion

the pronator teres is also a weak

flexor

the elbow flexors or extensors innervated by higher spinal segments

flexors

all heads of the triceps brachii have a common attachment on the common tendon to the olecranon of the ulna (distally), so the position of the ___ determines its ability to act (distal attachment)

forearm

the biceps brachii assist in pronating the forearm with

heavy loading

the ulnar collateral ligament supports the

hinge joint

pronation & supination occur in the

horizontal plane

the pronator teres is a 2 joint muscle & crosses the

humeralulnar & radialulnar joints

the trochlea is on the

humerus

the axis of movement for the elbow is through the

humerus & forearm

the brachialis crosses only the elbow joint and can therefore flex the elbow

in any position

the carrying angle is obvious

in extension

the long head of the triceps brachii attaches proximally to the

infraglenoid tubercle of scapula

the triceps can be a synergist to the biceps during

isometric co-contraction & when biceps is acting as supinator (to prevent elbow flexion & therefore active insufficiency of biceps)

the triceps is synergist to biceps during

isometric co-contraction & when biceps is acting as supinator to prevent elbow flexion & thus active insufficiency of biceps

the joint capsule blends with the

lateral collateral ligament

the posterior wrist extensors all have a common attachment point at the

lateral epicondyle

the radial collateral ligament connects the head of the radius to the

lateral epicondyle

in valgus, the distal bone segment is angled

laterally from the body's midline

only the ___ head of the triceps brachii crosses the shoulder joint

long head (with its scapular attachment)

the anterior wrist flexors all have a common attachment point at the

medial epicondyle

the groove for the ulnar nerve is under the

medial epicondyle

the pronator teres has 2 heads. the humeral head attaches to the ___ & the ulnar head attaches to the

medial epicondyle of the humerus; coronoid process of ulna

the medial cord leads to the

median & ulnar nerves

in extension, there is ___ contact between the radial head & the humerus

minimal

innervated by radial nerve

mostly extensors, except for brachioradialis (which is posterior compartment) BATE - triceps brachii - anconeus - extensor carpi radialis

the lateral cord leads to the

musculocutaneous nerve with a branch to median

the olecranon of the ulna slides into the

olecranon fossa of the humerus

in cubitus varus, the distal bone segment (hand) is angled

outward

after the plexus, spinal nerve innervation is not the main concern, but

peripheral nerve innervation

both the superior radialulnar & the inferior radialulnar joints are ___ joints

pivot

the radioulnar joint is ___ joint with __ df

pivot, 1 df

the wrist extensors are on the ___ side of the forearm

posterior

the posterior cord is in the

posterior division of the posterior compartment

nerves from the posterior divisions feed

posterior muscles - extensors

the brachioradialis in the posterior or anterior compartment

posterior, innervated by radial nerve

the superficial anterior compartment of the forearm contains the

pronator teres, flexor carpi radialis, palmaris, longus, flexor carpi ulnaris

these 2 fossa are above the capitulum

radial & coronoid (for coronoid process of ulna)

in flexion the radial head enters the

radial fossa (above capitulum)

the capitulum of the humerus articulates with the

radial head of the radius

the annular lig is important for

radialulnar joint function (surrounds the radial notch & helps it resist displacement when hand is pulled away from shoulder)

pronation of the forearm requires ___ rotation of the

radius

the capitulum articulates with the

radius head (the capitol is rad)

the long head of the triceps is the only one that crosses the shoulder joint and attaches to

scapula

the musculocutaneous nerve enters the forearm as the lateral cutaneous nerve (which attaches to radius) & provides

sensory innervation to the lateral aspect of forearm

the biceps brachii will become actively insufficient when

shoulder flexed, elbow flexed, supinated

the triceps brachii can become actively insufficient if the

shoulder is hyper-extended & elbow is extended

the shallow radial head ____ over the capitulum of the humerus

slides

during flexing, the trochlea ___ into the trochlear notch. the humerus is guided ___ because the trochlea & trochlear notch are at a slight angle.

slides; medially

the biceps brachii flexes the elbow joint when

supinated or in midposition

which 2 muscles attach to the lateral epicondyle?

supinator & anconeus

the anconeus is a ___ to pronation & supination

synergist

the supinator attaches to

the lateral epicondyle of the radius

the axis of movement for the elbow is

through the humerus & forearm (think criss-crossing the trochlea, with longitudinal dividing it in vertically & axis of flexion/extension dividing it horizontally at a slide angle from slightly up laterally to down horizontally)

if the shoulder is flexed, the ___ will become ___ insufficient to prevent elbow flexion

triceps, passively insufficient

the humeralulnar joint is a hinge joint and occurs where the

trochlea of the humerus meets the trochlear notch of the ulna

the trochlea articulates with the

trochlear notch of the ulna

the trochlea of the humerus articulates with the

trochlear notch of the ulna

the olecranon is part of the

ulna

the pronator quadratus has 2 heads and both attach to the

ulna

the fibrous capsule is reinforced by the

ulnar & radial collateral ligs

the head of the ulna fits into the

ulnar notch of the radius

the brachial plexus is formed by the

ventral rami