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39 Cards in this Set

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Functions of each lumbrical (2)
Each lumbrical can flex its finger at the metacarpophalangeal joint and extend its finger at the interphalangeal joints.
The 1st and 2nd lumbricals are innervated by the
median nerve
The 3rd and 4th lumbricals are innervated by the
deep branch of the ulnar nerve
Paralysis of a lumbrical results in
o Paralysis of a lumbrical results in hyperextension of its finger at the metacarpophalangeal joint and flexion of its finger at the interphalangeal joints.
How many dorsal interossei are there and what are they associated with
-There are four dorsal interossei
-The 1st dorsal interosseous is associated with the lateral side of the index finger,
-the 2nd dorsal interosseous with the lateral side of the middle finger,
-the 3rd dorsal interosseous with the medial side of the middle finger, and
-the 4th dorsal interosseous with the medial side of the ring finger.
-Each dorsal interosseous has two heads of origin
The collective actions of the dorsal interossei can be presented by the acronym DAB (3 total functions of the dorsal interossei)
-starting with the hand in the anatomical position, each Dorsal interosseous can ABduct its finger.
-Each dorsal interosseous can also flex the finger at its metacarpophalangeal joint and extend the finger at its interphalangeal joints.
What innervates the dorsal interossei and paralysis of it leads to what
-The dorsal interossei are all innervated by the deep branch of the ulnar nerve.
-Paralysis of the dorsal interossei results in an inability to spread apart the index, middle, and ring fingers
How many palmar interossei are there and what are they associated with
-There are three palmar interossei, numbered 1 through 3.
-The 1st palmar interosseous is associated with the medial side of the index finger,
-the 2nd palmar interosseous with the lateral side of the ring finger, and
-the 3rd palmar interosseous with the lateral side of the little finger.
The collective actions of the palmar interossei can be presented by the acronym PAD (3 total functions of the palmar interossei)
starting with the fingers abducted, each Palmar interosseous can ADduct its finger.
Each palmar interosseous can also flex the finger at its metacarpophalangeal joint and extend the finger at its interphalangeal joints.
What innervates the palmar interossei and paralysis of it leads to what
-The palmar interossei are all innervated by the deep branch of the ulnar nerve.
-Paralysis of the palmar interossei results in an inability to squeeze the fingers together along their sides.
What are the 3 Muscles of the Thenar Eminence and their functions
-Abductor pollicis brevis can abduct the thumb at its carpometacarpal and metacarpophalangeal joints.
-Flexor pollcis brevis can flex the thumb at its carpometacarpal and metacarpophalangeal joints.
-Opponens pollicis is the sole prime mover of opposition of the thumb.
3 Muscles of the Thenar Eminence Innervation and Paralysis leads to...
Ape Hand
-The muscles of the thenar eminence are all innervated by the recurrent branch of the median nerve; the recurrent branch arises from the median nerve distal to the carpal tunnel.
-Paralysis of the muscles of the thenar eminence results in an inability to oppose the thumb (because of paralysis of opponens pollicis) and weakness in abduction of the thumb (because of paralysis of abductor pollicis brevis).
-The prominence of the thenar eminence in the palm of the hand diminishes as the muscles of the thenar eminence progressively waste following paralysis.
The thumb becomes laterally rotated excessively at its carpometacarpal joint (because of the paralysis of opponens pollicis, one of whose actions during opposition of the thumb is to medially rotate the thumb at its carpometacarpal joint).
Consequently, paralysis of the muscles of the thenar eminence is said to produce an ape hand.
heads of origin of Adductor pollicis, functions (2), and innervation
-Adductor pollicis has two heads of origin: the transverse head originates from the shaft of the 3rd metacarpal, and the oblique head originates from the bases of the 2nd and 3rd metacarpals.
-Adductor pollicis can adduct the thumb at its carpometacarpal and metacarpophalangeal joints and flex the thumb at its metacarpophalangeal joint.
-Adductor pollicis is innervated by the deep branch of the ulnar nerve.
The 3 Muscles of the Hypothenar Eminence and their functions
-Abductor digiti minimi can abduct the little finger at its metacarpophalangeal joint.
-Flexor digiti minimi can flex the little finger at its metacarpophalangeal joint.
-Opponens digiti minimi can flex and laterally rotate the 5th metacarpal at its carpometacarpal joint; this action deepens the hollow of the palmar surface.
o
Abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi are all innervated by the...
Abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi are all innervated by the deep branch of the ulnar nerve.
Palmaris brevis - does what to skin and is innervated by what
Palmaris brevis can wrinkle the skin covering the hypothenar eminence.
Palmaris brevis is innervated by the superficial branch of the ulnar nerve.
An Emergency Room Test of Median Nerve Supply to the Intrinsic Muscles of the Hand
A quick test of the median nerve’s motor supply within the hand is to request the patient to touch the base of the little finger with the tip of the thumb. This maneuver cannot be executed if opponens pollicis is paralyzed.
An Emergency Room Test of Ulnar Nerve Supply to the Intrinsic Muscles of the Hand
A quick test of the ulnar nerve’s motor supply within the hand is to request the patient to clench a piece of paper tightly between the middle and ring fingers as you attempt to dislodge the paper. The paper cannot be tightly clenched between the fingers if the palmar and dorsal interossei are paralyzed.
Claw Hand - injury to what nerve causes this, what muscles are injured and which ones are spared
-Serious injury to the ulnar nerve in the axilla, arm, or forearm can result in the paralysis of all the intrinsic hand muscles innervated by the deep branch of the ulnar nerve (adductor pollicis, the 3rd and 4th lumbricals, all the palmar and dorsal interossei, abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi).
-Paralysis of the dorsal interossei restricts the fingers from being spread apart through abduction at their metacarpophalangeal joints. As previously explained, paralysis of the 3rd and 4th lumbricals results in hyperextension of the ring and little fingers at their metacarpophalangeal joints and flexion of these fingers at their interphalangeal joints. The index and middle fingers are spared hyperextension at their metacarpophalangeal joints and flexion at their interphalangeal joints because the 1st and 2nd lumbricals are innervated by the median nerve.
-Because the disfigured ring and little fingers assume the shape of a claw, paralysis of the intrinsic hand muscles innervated by the deep branch of the ulnar nerve is said to produce a claw hand.
Klumpke’s Palsy - which limb muscles are affected and why
Klumpke’s Palsy refers to the condition in which upper limb muscles are partially or completely paralyzed whose sole or major innervation is provided by C8 and/or T1 fibers.
This happens as a consequence of a lesion involving the C8 and T1 roots, the lower trunk, or the divisions of the lower trunk of the brachial plexus.
How can one get Klumpke's Palsy
Klumpke’s palsy frequently results from injury to the lower parts of the brachial plexus. Excessive traction on these parts of the brachial plexus is the most common mechanism of injury. Instances in which such an injury is sustained include accidents in which a person falling from a significant height grasps at some object to break the fall and in the process hyperabducts the arm.
If significant damage is sustained by both C8 and T1 fibers, the most important muscular actions compromised or lost by such damage are those of the...
If significant damage is sustained by both C8 and T1 fibers, the most important muscular actions compromised or lost by such damage are those of the intrinsic hand muscles. This is because C8 and T1 are the ONLY spinal nerves that provide innervation for not only the intrinsic hand muscles innervated by the deep branch of the ulnar nerve BUT ALSO the intrinsic hand muscles innervated by the median nerve. Consequently, the loss of the actions of both sets of intrinsic hand muscles eventually contorts the hand into a combination of a clawhand and an ape hand.
Cutaneous Innervation of the Hand - branches of the ulnar nerve
• On the palmar (volar) (anterior) surface of the hand, branches of the ulnar nerve supply the cutaneous innervation for the medial one-third of the palm of the hand and the medial one and a half digits.
Cutaneous Innervation of the Hand - branches of the median nerve
Branches of the median nerve supply the cutaneous innervation for the remainder of the palmar surface (the lateral two-thirds of the palm and the lateral three and a half digits).
The anterior hand surfaces receiving sensory innervation from the median nerve are the surfaces by which objects are primarily felt by the hand. It is for this reason that the median nerve is referred to as “the eye of the hand.”
The median and ulnar nerve branches that supply cutaneous innervation for the anterior surfaces of the digits vs. those that supply cutaneous innervation the anterior surface of the palm
-The median and ulnar nerve branches that supply cutaneous innervation for the anterior surface of the palm arise from their respective nerves PROXIMAL to the wrist and cross the wrist anterior to the flexor retinaculum.
-By contrast, the median and ulnar nerve branches that supply cutaneous innervation for the anterior surfaces of the digits arise from their respective nerves DISTAL to the flexor retinaculum.
On the dorsal (posterior) surface of the hand, branches of the ulnar nerve supply ...
On the dorsal (posterior) surface of the hand, branches of the ulnar nerve supply the medial third of the dorsum of the hand
On the dorsal (posterior) surface of the hand the superficial branch of the radial nerve supplies...
the superficial branch of the radial nerve supplies the lateral two-thirds of the dorsum of the hand
An Emergency Room Test of Median Nerve Supply to the Skin of the Hand
A quick test of the median nerve’s sensory supply within the hand is to ascertain whether the patient can sense a probe lightly applied to the palmar surface of the index finger.
An Emergency Room Test of Ulnar Nerve Supply to the Skin of the Hand
A quick test of the ulnar nerve’s sensory supply within the hand is to ascertain whether the patient can sense a probe lightly applied to the palmar surface of the little finger.
Carpal Tunnel Syndrome - what is it and how does it occur
-Entrapment or compression of the median nerve along its course through the carpal tunnel can produce median nerve damage from mechanical deformation and/or ischemia. -Most of the median nerve lesions are in the form of neuropraxia (a neuronal lesion in which local demyelination occurs in the absence of axonal disruption) or an axonotmesis (a neuronal lesion in which disruption of axons and their myelin sheaths occurs in the absence of disruption of the endoneurium and other connective tissue sheaths).
Carpal Tunnel Syndrome symptoms
In cases of insidious onset, pain and sensory deficits within the distribution of the digital cutaneous branches of the median nerve are typically the initial neurologic symptoms. Pain and hypalgesia may occur concomitantly as a result of the increased pressure both irritating some pain nerve fibers (thus producing pain) and damaging others (thereby diminishing sensitivity to pain).
A broad spectrum of injuries, diseases, and conditions can produce carpal tunnel syndrome... (6)
1)Fractures and dislocations at the wrist
2)chronic inflammatory conditions such as rheumatoid arthritis and gout, and repetitive wrist movements (particularly those involving forceful flexion of the hand) can produce the syndrome by tenosynovitis of the flexor tendons in the carpal tunnel and the attendant thickening of the synovial sheaths. Systemic conditions such as 3)hypothyroidism
4)diabetes mellitus, 5)acromegaly
6)systemic lupus erythematosus can produce the syndrome by retention of interstitial fluid and the attendant swelling of soft tissues.
The blood supply of the hand is mainly provided by two arterial arches which course through the palm of the hand (what are they and location of each)
the superficial palmar arch and the deep palmar arch. Whereas the superficial palmar arch lies anterior to the tendons of flexor digitorum profundus and superficialis, the deep palmar arch lies posterior to these tendons.
-The superficial palmar arch is the direct continuation of the...
-what does it anastomose with
-what do its its major branches supply
ulnar artery in the hand.
The ulnar artery gives off a deep branch immediately distal to the flexor retinaculum, and then curves laterally through the palm as the superficial palmar arch. The superficial palmar arch generally anastomoses in the lateral half of the palm with the superficial branch of the radial artery. The major branches of the superficial palmar arch are the digital arteries that supply the fingers.
The deep palmar arch is the direct continuation of the...
--what does it anastomose with
The deep palmar arch is the direct continuation of the radial artery in the hand.
The radial artery gives rise to a superficial branch upon entering the hand, and then curves medially through the palm as the deep palmar arch. The deep palmar arch generally anastomoses in the medial half of the palm with the deep branch of the ulnar artery.
What is the Princeps pollicis and what does it arise from
Princeps pollicis, which is a major artery of the thumb, typically arises from the radial artery in the hand before it turns into the deep palmar arch
What is the Radialis indicis and what does it arise from
Radialis indicis, which is a major artery of the index finger, typically arises from the radial artery in the hand before it turns into the deep palmar arch.
What does the Allen Test determine and how is it carried out - 5 steps
The Allen test can determine whether the ulnar and radial arteries both contribute blood supply to a patient’s hand. Each artery is tested separately as follows:
1)The patient is asked to make a tight fist. The capillary beds within the skin of the palm are thereby emptied of much of their blood content.
2)The examiner then applies pressure to both the ulnar and radial arteries at their palpation sites in the anterior forearm. This significantly blocks the blood flow into the palmar arches.
3)The patient is asked to unclench the fist, exposing the blanched pallor of the palmar surface.
4)The examiner releases the pressure on one artery and ascertains whether color is restored to the palmar surface within 2 to 4 seconds. The return of color indicates that the artery is a chief source of blood supply to the hand. (The average velocity of blood flow in a capillary is 1 mm/sec, and the average length of a blood capillary is 1 mm. Consequently, a subcutaneous blood capillary bed emptied of much of its blood content should, under normal conditions, become filled with blood within about 2 seconds after blood supply is restored.)
5)The entire test is then repeated with the other artery to ascertain that both arteries are supplying the palmar arches.
What dermatomes provide most of the sensory innervation to the skin of the thumb, index, middle, ring, and little fingers
-C6 provides most of the sensory innervation to the skin of the thumb
-C7 provides most of the sensory innervation to the skin of the index, middle, and ring fingers
-C8 provides most of the sensory innervation to the skin of the little finger.