Arm Review Flashcards
What is the normal carrying angle (cubitus valgus)?
10-15 degrees
T/F Carrying angle is greater in females (average 13 degrees) than males (average 10 deg).
True
What is the functional importance of a carrying angle?
- compensates for the change of orientation of the radius
- allows the axis of the hand to stay in the longitudinal plane
T/F Humero-ulnar joint is a very stable joint.
True
What motion do the Humero-ulnar joint and the humero-radial joint have?
Uni-axial motion
Radial collateral ligament attached to what two areas?
lateral epicondyle and annular ligament
Radial collateral ligament taut throughout what range of motion?
Flexion range
Anterior band of ulnar collateral ligament taut throughout what range of motion?
Flexion
Posterior band of ulnar collateral ligament taut throughout what range of motion?
Between 1/2 and full extension
Resting position of humero-ulnar joint?
70 deg flex with 10 deg supination
Resting position of humero-radial joint?
Full extension & supination
T/F No vascular supply to proximal scaphoid
True
What is the triangular fibrocartilage complex (TFCC)
- Biconcave articular disc attaches along the rim of the ulnar notch of the radius, fans out, attaches horizontally into the depression of the ulnar head & styloid process
- Continuous with ulnar collateral ligament
- Anterior and posterior aspects are continuous with the radioulnar joint capsule ligaments
What is the function of the TFCC?
- Primary stabilizer of the distal Radioulnar Joint
- Elastic cushion between ulnar head and triquetrum during wrist adduction- increases contact surface area
What creates the carpal tunnel?
Flexor retinaculum
What runs inside the carpal tunnel?
FDS, FDP, FPL, and median nerve
Function of the Flexor retinaculum?
Prevents bowstringing during wrist flexion
What carpals in lateral column of hand? Which digits?
Scaphoid, trapezium, 1st/2nd digits
What carpals in Intermediate column of hand? Which digits?
Lunate, capitate, 3rd digit
What carpals in Medial column of hand? Which digits?
Pisiform, triquetrum, hamate, 4th/5th digit
Intermetacarpal joints are connected by what?
dorsal, palmar and interosseous ligaments
___ metacarpal surface on a ____ proximal phalanx surface of MCP.
Convex
Concave
____ proximal phalanx on a ____ distal phalanx
convex
concave
What’s a palmar plate?
Fibrocartilage attachment off of the base of the anterior aspect of the proximal phalanx to the neck of the metacarpal (or distal phalanx to proximal phalanx)
What are the functions of the palmar plates?
- Increases the area of the articular surface
- Resist hyperextension with ligamentous attachment to proximal bony structure
- Reinforce the joint capsule
- Prevent impingement of flexor tendons during MCP flexion
- Protects articular cartilage in extension with impact
- Has healing capacity
What travels through finger pulleys?
Flexors of fingers
Along the phalangers, there are a series of arcuate and cruciate pulleys that function to do what?
stops bow stringing from occurring
What do you find deep to cruciate ligament in the fingers?
Synovial tendon sheath
Resting position of Radiocarpal/mid-carpal?
Slight palmar flexion/ slight ulnar deviation
Resting position of proximal carpal row/distal carpal row?
Slight palmar flexion
Resting position MCP and IPJ?
Slight flexion
Brachialis action? Innervated by what nerve?
- Elbow flexor
- Musculocutaneous
Brachioradialis action? Innervated by what nerve?
- elbow flexor, supinator in extreme pronation & pronator in extreme supination
- Radial nerve
What muscles is main flexor of elbow, but also supinator?
Biceps brachii
- Musculocutaneous
What 2 accessory muscles for elbow flexion?
ECRL (radial nerve) Pronator Teres (median nerve)
When do elbow flexors have peak mechanical advantage?
80-90
When does brachioradialis have peak mechanical advantage?
100-110
Triceps brachii origin and insertion? Innervated by?
- Posterior/lateral humerus and glenoid notch of scapula -> tendon insertion on olecranon process
- Radial nerve
Supinator action? INnervated by?
Unwinds the ulna
Radial nerve
At what degree of elbow flexion does the biceps brachii have the max efficiency for forearm supination?
90 elbow flexion
Pronator quadratus innervated by?
Anterior interosseous nerve
Pronator teres action is especially weak when elbow is in what position? Innervated by?
- weak action (especially when elbow is flexed)
- median nerve
When is flexion of the wrist by the brachioradialis most effective?
In mid-pronation
What are the tendons that make up to anatomic snuff box?
Abductor Pollicis Longus/EPB
Extensor Pollicis Longus
What are the contents of the anatomic snuff box?
Scaphoid and trapezium
Normal ROM of wrist abd/adduction?
AROM: Abduction-Adduction 15deg-0deg-45deg
ROM of abd/adduction of the wrist both decrease when wrist is in what position/s?
full flexion and extension secondary to tension in carpal ligaments
What carpals are in the proximal row?
Pisiform, Triquetrum, Lunate, Scaphoid
What carpals are in the distal row?
Hamate, Capitate, Trapezoid, Trapezium
The transverse carpal lig (flexor retinaculum) travel from where to where?
the pisiform and hamate to the scaphoid and trapezium
What are the 3 borders of guyon’s canal?
- Lateral border of the pisiform
- Transverse carpal ligament
- Pisohamate ligament
What are the contents of guyon’s canal?
- Ulnar Nerve- bifurcates late in the canal (superficial palmar cutaneous nerve)
- Ulnar Artery
