Lecture 8-- Hand Flashcards
What do you see in carpal tunnel
Since the median nerve is mainly responsible for innervation many of the thumb muscles, in carpal tunnel you see atrophy in the thenar eminence. They maintain some sensation over the palm of the hand because there is a branch of the median nerve that comes off before the carpal tunnel that provides sensation to the median distribution area of the hand.
What nerve Innervates the thenar muscles
The recurrent branch of the median nerve except the adductor pollicis which is the deep branch of the ulnar nerve.
What is unique about the thenar muscles
Abductor pollicis brevis and flexor pollicis both cross the MCP joint. The opponens pollicis inserts into the metacarpal so the fibers don’t cross the joint. Also this is the recurrent branch of the median nerve and it goes in between these two muscles.
Describe the webspace of the hand
On the palmar side the first webspace is the adductor pollicis if you flip over to the dorsal side it’s the first dorsal interossei.
The hypothenar muscles are all Innervated by what nerve
Deep branch of ulnar nerve
The flexor digiti minimi brevis is ____ to the abductor digiti minimi
Lateral
What are the short muscles Innervated by
The deep branch of the ulnar nerve except for lumbricals 1 and 2 which are the lateral and medial branches of the median nerve.
If you lose your ulnar nerve behind the medial epicondyle with an elbow fracture, will you still have flexion in digits four and five?
Yes, because flexor digitorum superficialis. You would not have flexion at the dips because you lose the FDP and would have some flexion at MCP and PIP because you still have the FDS.
What is the main contributor to the superficial palmar arch
The ulnar artery
Goes behind or around the trapezium, scaphoid, and first metacarpal. It enters the palm by passing the heads of the first dorsal intrrossei. It turns medial and passes between the heads of the adductor pollicis.
Radial artery
What is the main thing that forms the deep palmar arch
Radial artery
What are the terminal branches of the radial artery
Dorsal carpal arch (dorsal metacarpal–>dorsal digital)
Superficial branch (superficial palmar arch)
Deep palmar arch (palmar metacarpal–> common palmar digital)
Princeps pollicis off deep arch
Radialis indicis off deep arch
Enters the hand through the carpal tunnel. Gives off a recurrent branch in the thenar compartment and splits lateral and medial branches to the lumbricals.
Median nerve
Distribution of the median nerve
Motor to the thenar muscles except The adductor pollicis and half of the flexor pollicis brevis–deep head–both deep branch of ulnar nerve. And lumbricals one and two
Sensory: Palm and dorsum (from dip and ip joints distal) of the hand lateral to the line bisecting the 4th digit
What would you see if the median nerve was compressed in carpal tunnel syndrome
Loss of sensory not in the palm but out in the digits and loss of the thenar eminance. You have the adductor pollicis and all the muscles supplied by the radial and ulnar nerves and the flexor pollicis longus. Which means you can do enough flexion to do opposition. So you have weakening of actions but not atrophy.
What would happen if you compress the ulnar nerve in guyon’s canal
Claw hand, you would notice its opposite of the Z motion. It is extension at the MCPs and flexion at the IPs instead of the opposite. Much worse in the fourth and fifth digits, but we see it in others as well because it Innervates the interossei. It’s called klumpke’s palsy and gets rid of c8 and t1. There is an imbalance between the remaining flexors and extensors. Whether it happens at the brachial plexus, elbow, or hand it will be this. If at elbow or above you get the FDP and FCU knocked out and no ulnar deviation. Lumbricals 2 and 3 are supplied by the median nerve
The superficial radial branch of the radial nerve gives off what branch
The dorsal digital branches
Distribution of the superficial branch of the radial nerve
Sensory to the dorsum of the hand lateral to a line bisecting the 4th digit from the dip and ip joints proximal
Describe the regions of the hand
Central: between the palmar aponeurosis and the intermuscular septum
Thenar: base of the thumb
Hypothenar: over 5th metacarpal
Adductor-interossei: includes the muscles that make up the deep palm and the dorsum of the hand.
Dorsum: thin superficial fascia and deep fascia in which the dorsal venison network lies.
What is contained in the central region of the hand
tendons of FDS, FDP, AND FPL. lumbricals, superficial and deep palmar arches, and median and ulnar nerves.
What does the thenar region of the hand contain
Tendon of FPL, thenar muscles except the adductor pollicis, and the recurrent branch of the median nerve.
What is contained in the hypothenar compartment of the hand
Contains the hypothenar muscles and the deep branch of the ulnar nerve.
What is contained in the dorsum region of the hand
TENDONS OF ED, EI, EDM, EPB, AND EPL, and the dorsal carpal arterial arch and branches.
The ____ encircles the head of the radius, holding in position on the ulna
Annular ligament
The wrist is a what kind of joint
Condyloid
What are the ligaments of the wrist joint
Palmar radiocarpal
Dorsal radiocarpal
Ulnar collateral
Radial collateral
What are the articulations in the wrist joint
Intercarpal
Carpometacarpal
Intermetacarpal
Metacarpophalangeal
