Nerve and Tendon Injuries

Question 1

What is a sesamoid bone?

Give a common example

Answer 1

In anatomy, a sesamoid bone is a bone embedded within a tendon or a muscle

Patella

Question 2

What fibres attach tendons to bone?

Answer 2

Sharpey’s fibres

Question 3

What are tenocytes?

Answer 3

Elongated fibroblast type cells. The cytoplasm is stretched between the collagen fibres of the tendon. They have a central cell nucleus with a prominent nucleolus. Tendon cells have a well-developed rough endoplasmic reticulum and they are responsible for synthesis and turnover of tendon fibres and ground substance.

Question 4

What type of collagen makes up the structure of tendons along with tenocytes?

Answer 4

Type 1

Question 5

Collagen bondles arrange into fascicles which arange into tendon.

What covers these three structures?

Answer 5

Collagen bundles covered by endotenon

Fascicles covered by paratenon

Tendon covered by epitenon

Question 6

What is a vinculum?

Answer 6

a connecting band of tissue, such as that attaching a flexor tendon to the bone of a finger or toe

Question 7

Fine network of blood vessels exist in which covering of tendon structure?

Answer 7

Paratenon

covers fascicles

Question 8

Immobility reduces what in joints?

Answer 8

Water content and glycosaminoglycan concentration and strength

Question 9

What can cause tendon degeneration over time as we age?

Answer 9

Intrasubstance mucoid degeneration

Question 10

What are the signs and symptoms of tendon degeneration?

Answer 10

May be swollen
Painful
Tender
May be asymptomatic

?Precursor to rupture

Question 11

Give an example of tendon inflammation

Answer 11

de Quervain’s stenosing tenovaginitis

Question 12

What is de Quervain’s stenosing tenovaginitis?

What causes it, What is its presentation, What test can you perform?

Answer 12

Tendons of EPB and APL passing through common tendon sheath at radial aspect of wrist

Swollen, tender, hot and red

Positive Finkelstein’s test

Question 13

What is Finkelstein’s test?

Answer 13

To perform the test, the examining physician or therapist grasps the thumb and ulnar deviates the hand sharply, as shown in the image. If sharp pain occurs along the distal radius, de Quervain’s tenosynovitis is likely

Question 14

What is Eichhoff’s test?

Why is Finkelstein’s test used more?

Answer 14

Ask patients to flex their thumb and clench their fist over the thumb before ulnar deviation, but with ulnar deviation performed by the practitioner.

Eichhoff’s test is commonly confused with Finkelstein’s test. However the Eichhoff’s test may produce false positive results, while a Finkelstein’s test performed by a skilled practitioner is unlikely to produce a false positive

Question 15

Where does enthesiopathy give pain?

Give a common example

Answer 15

More usually at muscle origin rather than tendon insertion

Lateral humeral epicondylitis (tennis elbow)
-Common extensor origin

Question 16

Give a common example of traction apophysitis

Answer 16

Osgood Schlatter’s disease

Question 17

What is Osgood Schlatter’s disease?

What is it characterised by?

What are the risk factors?

Answer 17

Osgood–Schlatter disease aka apophysitis of the tibial tubercle, is an inflammation of the patellar ligament at the tibial tuberosity.

It is characterized by a painful bump just below the knee and is most often seen in young adolescents.

Risk factors include overuse (especially in sports involving running, jumping and quick changes of direction) and adolescent growth spurts.

Question 18

What is Sever’s disease?

How does it present?

Answer 18

Traction apophysitis at insertion of TA into os calcis
(inflammation of the growth plate in the heel of growing children, typically adolescents)

The condition presents as pain in the heel and is caused by repetitive stress to the heel and is thus particularly common in active children.

It usually resolves when the bone has completed growth or activity is lessened.

Question 19

What is an apophysis?

Answer 19

The apophysis is a normal bony outgrowth that arises from a separate ossification centre and fuses with the bone in course of time. The apophysis is a site of tendon or ligament attachment, as compared to the epiphysis which contributes to a joint.

Question 20

What is an avulsion fracture?

Answer 20

An avulsion fracture is an injury to the bone in a location where a tendon or ligament attaches to the bone. When an avulsion fracture occurs, the tendon or ligament pulls off a piece of the bone.

Question 21

Give a common example of avulsion fracture

What is it, What does the effected area look like?

Answer 21

Insertion of extensor tendon into dorsum of base of distal phalanx of finger

Forced flexion of extended finger

Question 22

How do you treat mallet finger?

Answer 22

Mallet splint

-Immobilises so it can heal

Question 23

How can you examine an achilles tendon rupture?

Answer 23

“Positive” Simmonds (squeeze) test
-Get them to kneel on chair and squeeze calf -> if foot plantar flexes then tendon ok

Palpable tender gap

Question 24

What is the mechanism of rupture in achilles tendon tear?

Answer 24

Pushing off with weightbearing forefoot whilst extending knee joint (53%)
-e.g. sprint starts or jumping movements

Unexpected dorsiflexion of ankle (17%)
-e.g. slipping into hole

Violent dorsiflexion of plantarflexed foot (10%)
-e.g. fall from height

Question 25

What is the classic situation for an achilles tendon tear?

Answer 25

Raquet sport

Accuse person behind of hitting or kicking

Question 26

What is the epidaemiology of achilles tendon rupture?

Answer 26

Males 2:1 females

Peak age 30-40y, rises again >60y

Incidence rising (up 30-40% since 1980)

Question 27

How do you treat achilled tendon rupture?

Answer 27

Conservative

• PoP cast for 10 wks
• —Higher risk of re-rupture

Operative

• With open repair and earlier mobilisation
• –For younger active patients
• –Risk of wound problems
• –Re-rupture rate lower but still occurs

Question 28

What is Tennis leg (aka plantaris syndrome)?

Answer 28

Tear of medial head of gastrocnemius at musculotendinous junction with achilles tendon

Question 29

Describe the healing process of tendons

What initiates it? What phases? how strong?

Answer 29

Tendon healing initiated by fibroblasts (from epitenon) and macrophages

3 phases:

• Inflammatory
• Fibroblastic (collagen producing)
• Remodelling

Tendon repairs are wekest at 7-10 days; regain most of original strength by 3-4 weeks and achieve maximum strength in 6 months

Question 30

How are axons arranged to form nerves?

What covers these 3 structures?

Answer 30

Axons are coated with endoneurium and grouped into,

Fascicles (nerve bundles) covered with perineurium, these are arranged to form the,

Nerve which is covered with epineurium

Question 31

Describe the 3 types of nerve fibres

Diameter, myelination, speed, and an example of what it does

Answer 31

Type A:

• Diatemeter = 10-20um
• Myelination = heavy
• Speed = fast
• Example = touch

Type B:
-Diameter =

Question 32

What is neurapraxia?

Answer 32

Neurapraxia is a disorder of the peripheral nervous system in which there is a temporary loss of motor and sensory function due to blockage of nerve conduction, usually lasting an average of six to eight weeks before full recovery

Question 33

Describe the pathophysiology of neurapraxia

Answer 33

This condition is typically caused by a blunt neural injury due to external blows or shock-like injuries to muscle fibers and skeletal nerve fibers, which leads to repeated or prolonged pressure buildup on the nerve. As a result of this pressure, ischemia occurs, a neural lesion results, and the human body naturally responds with edema extending in all directions from the source of the pressure. This lesion causes a complete or partial action potential conduction block over a segment of a nerve fiber and thus a reduction or loss of function in parts of the neural connection downstream from the lesion, leading to muscle weakness.

Neurapraxia results in temporary damage to the myelin sheath but leaves the nerve intact and is an impermanent condition; thus, Wallerian degeneration does not occur in neurapraxia

Question 34

What is axonotmesis?

Answer 34

Axonotmesis is a disruption of nerve cell axon, with Wallerian degeneration occurring below and slightly proximal to the site of injury. If axons and their myelin sheath are damaged, but Schwann cells, the endoneurium, perineurium and epineurium remain intact, it is called axonotmesis. Axonotmesis is usually the result of a more severe crush or contusion than neuropraxia

Question 35

What is neurotmesis?

Answer 35

Neurotmesis (in Greek tmesis signifies “to cut”) is part of Seddon’s classification scheme used to classify nerve damage. It is the most serious nerve injury in the scheme. In this type of injury, both the nerve and the nerve sheath are disrupted. While partial recovery may occur, complete recovery is impossible.

Question 36

What is morton’s neuroma?

Answer 36

Morton’s neuroma is a benign neuroma of an intermetatarsal plantar nerve, most commonly of the second and third intermetatarsal spaces (between 2nd−3rd and 3rd−4th metatarsal heads), which results in the entrapment of the affected nerve.

The main symptoms are shooting pain and/or numbness, sometimes relieved by removing footwear.

Question 37

What is the first sensory modality to return after nerve injury?

Answer 37

Pain

Question 38

How slow is regeneration of nerves?

Answer 38

1mm/day

Question 39

Proximal axonal budding occurs after how long?

Answer 39

1 month delay

Question 40

What simple examination test can you use to assess healing of nerve injury of hand?

Answer 40

Tinel’s sign

paraesthesiae will be felt as far distally as regeneration has progressed