Term | Definition |
the elbow complex includes... | 3 bones, 3 ligaments, 2 joints, and 1 capsule |
elbow joint | the articulation of the humerus with the ulna and radius |
on the humerus the trochlea articulates with... | the trochlear notch of the ulna |
the capitulum articulates with | the head of the radius |
the elbow is a... | uniaxial hinge joint |
the elbow allows only... | flexion and extension |
measured from the 0 degree position of extension, the joint has approximately... | 145 degrees of flexion |
the olecranon process of the ulna fitting into the olecranon fossa of the humerus blocks... | active hyperextension of the elbow |
some individuals are able to hyperextend a few degrees due to... | laxity of ligaments rather than bony structure |
radioulnar joint | the articulation between the radius and ulna |
at the proximal end of the radioulnar joint... | the head of the radius pivots within the radial notch of the ulna, forming the superior or proximal radioulnar joint |
due to the shape of the radius, the distal end of the radius... | rotates around the distal end of the ulna, forming inferior or distal radioulnar joint |
the radioulnar joint is a uniaxial pivot joint, allowing only... | pronation and supination of the forearm |
measured from the neutral position or midposition, there are approximately... | 90 degrees of supination and 80 degrees of pronation |
the radius moves... | around the ulna |
carrying angle | in the anatomical position, the longitudinal axes of the humerus and forearm form an angle |
the distal end of the humerus has two convex areas: | the trochlea articulating with the ulna and the capitulum articulating with the radius. |
the concave trochlear notch is | at the proximal end of the ulna |
the concave radial head is | at the proximal end of the radius |
infraglenoid tubercle | the raised portion on the inferior lip of the glenoid fossa that provides attachment of the long head of the triceps muscle |
supraglenoid tubercle | raised portion on the superior lip of the glenoid fossa that provides attachment for the long head of the biceps muscle |
coracoid process | projection on the anterior surface that provides attachment for the short head of the biceps muscle |
trochlea | located on the medial side of the distal end; articulates with the ulna |
capitulum | on the lateral side next to the trochlea; articulates with head of radius |
medial epicondyle | located on the medial side of the distal end above the trochlea; larger and more prominent than the lateral epicondyle. it provides attachment for the pronator teres muscle |
lateral epicondyle | located on the lateral side of the distal end above the capitulum; provides attachment for the anconeus and supinator muscles |
lateral supracondylar ridge | located above the lateral epicondyle; provides attachment for the brachioradialis muscle |
olecranon fossa | located on the posterior surface between the medial and lateral epicondyles; articulates with the olecranon process of the ulna |
ulna | medial bone of the forearm lying parallel to the radius. |
olecranon process | located at the porximal end of the ulna, on the posterior surface; forms the prominent point of the elbow and provides attachment for the triceps muscle |
trochlear notch | also called the semilunar notch; articulates with the trochlea of the humerus; makes up the anterior surface at the proximal end |
coronoid process | located just below the trochlear notch; with the ulnar tuberosity, provides attachment for the brachialis muscle |
radial notch | located at the proximal end on the lateral side just distal to the trochlear notch; articulation point for the head of the radius |
ulnar tuberosity | located below the coronoid process; provides an attachment for the brachialis muscle |
styloid process | at the distal end on the posterior medial surface |
ulnar head | at the distal end on the lateral surface; the ulnar notch of the radius pivots around it during pronation and supination |
radial head | proximal end; has a cylinder shape with a depression in the superior surface where it articulates with the capitulum of the humerus |
radial tuberosity | located on the medial side near the proximal end; provides attachment for the biceps muscle |
styloid process | located on the posterior later side of the radius at the distal end; provides attachment for the brachioradialis muscle |
the three ligaments of the elbow are... | the medial and lateral collateral ligaments and the annular ligament |
medial collateral ligament | triangular & spans medial side of the elbow. it attaches on the medial epicondyle of the humerus and runs obliquely to the medial sides of the coronoid process and olecranon process of the ulna |
lateral collateral ligament | triangular, attaches proximally on the lateral epicondyle of the humerus and distally on the annular ligament and the lateral side of the ulna. |
annular ligament | attaches anteriorly and posteriorly to the radial notch of the ulna encompassing the head of the radius and holding it against the ulna |
interosseous membrane | broad, flat membrane located between the radius and the ulna for most of their length. it keeps the two bones from separating and provides more surface area for attachment of the forearm and wrist muscles |
the muscles of the elbow and forearm | brachialis, brachioradialis, biceps, supinator, triceps, anconeus, pronator teres, pronator quadratus |
workhorse of the elbow joint | brachialis muscle |
origin of the brachialis muscle | distal half of humerus, anterior surface |
origin of the biceps brachii muscle | long head: supraglenoid tubercle of the scapula short head: coracoid process of scapula |
origin of the brachioradialis muscle | lateral supracondylar ridge on the humerus |
origin of the triceps muscle | long head: infraglenoid tubercle of scapula lateral head: inferior to greater tubercle on posterior humerus. Medial head: posterior surface of humerus |
origin of the anconeus muscle | lateral epicondyle of humerus |
origin of the pronator teres muscle | medial epicondyle of humerus and coronoid process of ulna |
origin of the pronator quadratus muscle | distal 1/4 of ulna |
origin of the supinator muscle | lateral epicondyle of humerus and adjacent ulna |
insertion of the brachialis muscle | coronoid process and ulnar tuberosity of the ulna |
insertion of the biceps brachii muscle | radial tuberosity of the radius |
insertion of the brachioradialis muscle | styloid process of the radius |
insertion of the triceps muscle | olecranon process of ulna |
insertion of the anconeus muscle | lateral and inferior to olecranon process of the ulna |
insertion of the pronator teres muscle | lateral aspect of radius at its midpoint |
insertion of the pronator quadratus muscle | distal 1/4 of radius |
insertion of the supinator muscle | anterior surface of the proximal radius |
action of the brachialis muscle | elbow flexion |
action of the biceps brachii muscle | elbow flexion, forearm supination (and Jason had us write in shd flex) |
action of the brachioradialis muscle | elbow flexion |
action of the triceps muscle | elbow extension (wrote in helps with shd ext) |
action of the anconeus muscle | not a prime mover in any joint action; assists in elbow extension |
action of the pronator teres muscle | forearm pronation, assistive in elbow flexion |
action of the pronator quadratus muscle | forearm pronation |
action of the supinator muscle | forearm supination |
nerve that innervates the brachialis muscle | musculocuateous nerve C5, C6 |
nerve that innervates the biceps brachii muscle | musculocuateous nerve C5, C6 |
nerve that innervates the brachioradialis muscle | radial nerve C5, C6 |
nerve that innervates the triceps muscle | radial nerve C7, C8 |
nerve that innervates the anconeus muscle | radial nerve C7, C8 |
nerve that innervates the pronator teres muscle | median nerve C6, C7 |
nerve that innervates the pronator quadrauts muscle | median nerve C8, T1 |
nerve that innervates the supinator muscle | radial nerve C6 |
lateral epicondylitis | tennis elbow, common overuse condition that affects the common extensor tendon where it inserts into the lateral epicondyle of the humerus. The extensor carpi radialis brevis is particularly affected. |
medial epicondylitis | golfers elbow, inflammation of the common flexor tendon that inserts into the medial epicondyle. overuse condition that results in tenderness over the medial epicondyle and pain on resisted wrist flexion |
little league elbow | overuse injury of the medial epicondyle, usually caused by a repetitive throwing motion. seen in young baseball players who have not reached skeletal maturity |
pulled elbow or nursemaid's elbow | seen in kids under 5 who have had a sudden strong traction force on the arm. often when adults pulls suddenly or child falls away while being held by arm. force causes radial head to sublux out from under annular ligament |
elbow dislocation | is caused when a great deal of force is applied to an elbow that is in a slightly flexed position. causes the ulna to slide posterior to the distal end of the humerus |
supracondylar fractures | most common fractures in children, caused by falling on the outstretched hand. the distal end of the humerus fractures just above the condyles. |
Volkmann's ischemic contracture | rare but potentially devastating ischemic necrosis of the forearm muscles caused by damage to the brachial artery |
synovial joint shapes can be... | irregular (plane), hinge, pivot, condyloid, saddle and ball-and-socket |
synovial joints can have how many axes? | 0-3 |
actively insufficient | when a muscle has contracted (shortened) over all its joints as far as it can |
passively insufficient | when a muscle has elongated (stretched) over all of its joints as far as possible |
an activity can be an open- or closed-kinetic-chain movement, depending on whether... | the distal segment is fixed |
the concave-convex rule | has the convex joint surface moving in a direction opposite to the movement of the body segment and the concave joint surface moving in the same direction as the body segment |