Joint Biomechanics
What is the arthrokinematics for elbow flexion at the radiohumeral joint?
roll anterior and glide anterior
- concave on convex
- roll and glide in same direction
Which muscle is innervated by the musculocutaneous nerve, attaches at the coracoid process, and is the main flexor muscle of the elbow?
Brachialis muscle!
What artery provides blood supply to an upper motor neuron in the primary motor cortex for the right arm?
Middle cerebral artery -Superior division
Which ligaments resists Varus and external rotation?
- Radial collateral ligament
- Lateral (ulnar) collateral ligament
Note* - the ulnar collateral ligament also resists flexion
What muscles are in the hypothenar compartment and what are they innervated by?
1. abductor digiti minimi, flexor digiti minimi, opponens digiti minimi
2. Deep branch of Ulnar Nerve
The kinematics of the Radioulnar joints ROM for daily living tasks, what is the degree of supination and pronation in each direction for normal functioning?
50 degrees of each pronation and supination
What muscle attaches to the infraglenoid tubercle and is innervated by the radial nerve?
Triceps Brachii- long head
1. Assessing the dermatomal sensation to the lateral forearm and the thumb, which dermatome are you assessing?
2. Assessing the dermatomal sensation to the middle finger, which dermatome are you assessing?
1. C6
2. C7
Which ligaments resist Valgus and flexion?
Medial collateral ligament (anterior and posterior fibers)
- Note* anterior fibers of medial collateral ligament also resist extension
What are the action of the lumbrical 1st and 2nd and what nerve innervates them?
Flexion at the MCP joints and extend IP joints 2-3
Median nerve (C8, T1)
1. What is the scapulohumeral rhythm, and what does it mean?
2. What is the greatest amount of scapular motion?
1. 2 glenohumeral and 1 scapulothoracic
2. 180 degrees
- For every 3 degrees of shoulder abduction, 2 degrees come from GH and 1 comes from ST
- 120 deg = GH joint
- 60 deg = ST joint
Which muscle is innervated by the dorsal scapular nerve and helps with scapular elevation?
Levator scapulae
In substantia nigra compacta which neurotransmitter would be released if the the direct pathway was active to encourage more movement?
Dopamine
Which ligament forms a protective arch over humeral head which prevents superior displacement from gleniod?
1. coracoacromial ligament
What 10 things go through the carpal tunnel?
(antero-medial flexor/pronator side)
1 Median nerve
4 Flexor digitorum profundus tendons
4 Flexor digitorum superficialis tendons
flexor pollicis longus
What are the arthrokinematics happening at the glenohumeral joint when the arm goes into adduction?
lateral roll of the humerus and superior glide
Which muscle is in the intermediate or second layer of the antero-medial compartment?
Flexor digitorum superficialis
What is the dermatome for the middle finger & which myotome would perform abduction of the fingers?
C7
and
T1
Which ligament resists distraction of the radius and external rotation?
Annular ligament
What are the outcropping muscles?
Abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
1. 1st CMC joint arthrokinematics during adduction is what?
2. What type of joint is this?
1. Posterior roll and anterior glide
- convex on concave
2. saddle joint
Which muscle goes through extensor tunnel 4 and is innervated by the deep branch of the radial nerve?
Extensor digitorum
1. Which artery would supply the ventral horn of the spinal cord?
2. Which myotome would allow for elbow extension?
1. Anterior spinal artery
2. C7
Which ligament and muscles limit supination?
TFCC (the palmar capsular ligament), pronator teres/quadratus, flexor carpi radialis, extrinsic finger flexors
Which muscle is innervated by the radial nerve and passes through the 5th extensor tunnel of the wrist?
Extensor digiti minimi