Struthers' ligament

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Diagram showing location of Struthers' ligament Struthers' ligament.svg
Diagram showing location of Struthers' ligament
Illustration by John Struthers, 1854: a) osseous process b) ligament Ligament of Struthers 1854.jpg
Illustration by John Struthers, 1854:
a) osseous process
b) ligament

Struthers' ligament is a feature of human anatomy consisting of a band of connective tissue at the medial aspect of the distal humerus. It courses from the supracondylar process of the humerus (also known as avian spur) to the medial humeral epicondyle. [2] It is not a constant ligament, [3] [4] [5] and can be acquired or congenital. The structure was highlighted by John Struthers, who discussed the feature's evolutionary significance with Charles Darwin. Struthers originally reported that the ligament usually arose at a position 3.2 to 6.4 cm from the medial condyle, being 1.2 to 1.9 cm in length, and nearer to the anterior than the medial border of the humerus. [1]

Contents

The clinical significance of this structure is due to the median nerve and brachial artery which may pass underneath the "arch" formed by the process and ligament over the humeral body. Within this space the nerve may be compressed leading to supracondylar process syndrome. [6] [7] [8] [9] The ligament may also affect the ulnar nerve after an anterior transposition surgery, which is a commonly performed to manage patients with a cubital tunnel syndrome, a form of ulnar nerve entrapment. It is unlikely that the ulnar nerves are affected in patients without transposition surgeries. [10]

Prevalence

The ligament is not always present, [11] and there is some debate as to its prevalence. Struthers originally estimated that it was present in 1% of humans. [2]

Historical significance

The structure was originally depicted by Tiedemann, [12] and later by Knox in the early 19th century, [13] but John Struthers was the first to draw attention to this structure in 1848 as a "peculiar process" that bore curious resemblance to anatomy that he had seen in cats. This observation was one of many that Struthers made in subsequent investigations of vestigial and rudimentary structures, and in sharing these observations with his contemporary, Charles Darwin, provided significant evidence for the theories of evolution. Charles Darwin took the ligament to mean that humans and other mammals had a common ancestor, and used Struthers' work as evidence in Chapter 1 of his Descent of Man (1871). [14] [15] Struthers went on to create a museum of Comparative Anatomy filled with zoological specimens to illustrate Darwin's theory of common descent. [16]

Related Research Articles

Humerus Long bone of the upper arm

The humerus is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a rounded head, a narrow neck, and two short processes. The body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes, and 3 fossae. As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons.

Ulnar nerve

In human anatomy, the ulnar nerve is a nerve that runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is common. This nerve is directly connected to the little finger, and the adjacent half of the ring finger, innervating the palmar aspect of these fingers, including both front and back of the tips, perhaps as far back as the fingernail beds.

Hamate bone

The hamate bone or unciform bone is a bone in the human wrist readily distinguishable by its wedge shape and a hook-like process ("hamulus") projecting from its palmar surface.

Ulnar collateral ligament of elbow joint

The ulnar collateral ligament is a thick triangular band at the medial aspect of the elbow uniting the distal aspect of the humerus to the proximal aspect of the ulna.

Cubital tunnel

The cubital tunnel is a space of the dorsal medial elbow which allows passage of the ulnar nerve around the elbow. It is bordered medially by the medial epicondyle of the humerus, laterally by the olecranon process of the ulna and the tendinous arch joining the humeral and ulnar heads of the flexor carpi ulnaris. The roof of the cubital tunnel is elastic and formed by a myofascial trilaminar retinaculum.

Flexor carpi ulnaris muscle

The flexor carpi ulnaris (FCU) is a muscle of the forearm that flexes and adducts at the wrist joint.

The flexor pollicis longus is a muscle in the forearm and hand that flexes the thumb. It lies in the same plane as the flexor digitorum profundus.

The pronator teres is a muscle that, along with the pronator quadratus, serves to pronate the forearm. It has two attachments, to the medial humeral supracondylar ridge and the ulnar tuberosity, and inserts near the middle of the radius.

Flexor retinaculum of the hand

The flexor retinaculum is a fibrous band on the palmar side of the hand near the wrist. It arches over the carpal bones of the hands, covering them and forming the carpal tunnel.

Ulnar canal

The ulnar canal or ulnar tunnel (also known as Guyon's canal or tunnel) is a semi-rigid longitudinal canal in the wrist that allows passage of the ulnar artery and ulnar nerve into the hand. The roof of the canal is made up of the superficial palmar carpal ligament, while the deeper flexor retinaculum and hypothenar muscles comprise the floor. The space is medially bounded by the pisiform and pisohamate ligament more proximally, and laterally bounded by the hook of the hamate more distally. It is approximately 4 cm long, beginning proximally at the transverse carpal ligament and ending at the aponeurotic arch of the hypothenar muscles.

Anterior interosseous nerve

The anterior interosseous nerve is a branch of the median nerve that supplies the deep muscles on the anterior of the forearm, except the ulnar (medial) half of the flexor digitorum profundus. Its nerve roots come from C8 and T1.

Fascial compartments of arm

The fascial compartments of arm refers to the specific anatomical term of the compartments within the upper segment of the upper limb(the arm) of the body. The upper limb is divided into two segments, the arm and the forearm. Each of these segments is further divided into two compartments which are formed by deep fascia – tough connective tissue septa (walls). Each compartment encloses specific muscles and nerves.

Cubitus varus Deformity involving inward deviation of an extended forearm

Cubitus varus is a common deformity in which the extended forearm is deviated towards midline of the body.

Ulnar nerve entrapment

Ulnar nerve entrapment is a condition where the ulnar nerve becomes physically trapped or pinched, resulting in pain, numbness, or weakness, primarily affecting the little finger and ring finger of the hand. Entrapment may occur at any point from the spine at cervical vertebra C7 to the wrist; the most common point of entrapment is in the elbow. Prevention is mostly through correct posture and avoiding repetitive or constant strain. Treatment is usually conservative, including medication, activity modification and exercise, but may sometimes include surgery. Prognosis is generally good, with mild to moderate symptoms often resolving spontaneously.

Ulnar neuropathy

Ulnar neuropathy is a disorder involving the ulnar nerve. Ulnar neuropathy may be caused by entrapment of the ulnar nerve with resultant numbness and tingling. Motor function can be assessed by testing for a positive Froment's sign, or making an OK sign, little finger abduction can be tested as well.

Elbow Joint between the upper and lower parts of the arm

The elbow is the visible joint between the upper and lower parts of the arm. It includes prominent landmarks such as the olecranon, the elbow pit, the lateral and medial epicondyles, and the elbow joint. The elbow joint is the synovial hinge joint between the humerus in the upper arm and the radius and ulna in the forearm which allows the forearm and hand to be moved towards and away from the body.

Supracondylar humerus fracture

A supracondylar humerus fracture is a fracture of the distal humerus just above the elbow joint. The fracture is usually transverse or oblique and above the medial and lateral condyles and epicondyles. This fracture pattern is relatively rare in adults, but is the most common type of elbow fracture in children. In children, many of these fractures are non-displaced and can be treated with casting. Some are angulated or displaced and are best treated with surgery. In children, most of these fractures can be treated effectively with expectation for full recovery. Some of these injuries can be complicated by poor healing or by associated blood vessel or nerve injuries with serious complications.

Median nerve palsy

Injuries to the arm, forearm or wrist area can lead to various nerve disorders. One such disorder is median nerve palsy. The median nerve controls the majority of the muscles in the forearm. It controls abduction of the thumb, flexion of hand at wrist, flexion of digital phalanx of the fingers, is the sensory nerve for the first three fingers, etc. Because of this major role of the median nerve, it is also called the eye of the hand. If the median nerve is damaged, the ability to abduct and oppose the thumb may be lost due to paralysis of the thenar muscles. Various other symptoms can occur which may be repaired through surgery and tendon transfers. Tendon transfers have been very successful in restoring motor function and improving functional outcomes in patients with median nerve palsy.

Supracondylar process of the humerus

The supracondylar process of the humerus is a variant bony projection on the anteromedial aspect of the upper arm bone (humerus), about 5-6 cm above the medial epicondyle. It is directed downward, forward and medially pointing to the medial epicondyle. A fibrous band, Struthers ligament, may connect this process to the medial epicondyle. This variation has a prevalence of 0.68% and is significantly more common in women than in men.

Epitrochleoanconeus muscle

The epitrochleoanconeus muscle is a small accessory muscle of the arm which runs from the back of the inner condyle of the humerus over the ulnar nerve to the olecranon.

References

  1. 1 2 Struthers, John, 1854. "On some points in the abnormal anatomy of the arm".
  2. 1 2 De Jesus R, Dellon AL (May 2003). "Historic origin of the "Arcade of Struthers"". J Hand Surg Am. 28 (3): 528–31. doi:10.1053/jhsu.2003.50071. PMID   12772116.
  3. ↑ Hommel U, Bellée H, Link M (1989). "[The validity of parameters in neonatal diagnosis and fetal monitoring of breech deliveries. 1. Neonatal status after breech delivery]". Zentralbl Gynakol (in German). 111 (19): 1293–9. PMID   2588859.
  4. ↑ Varlam H, St Antohe D, Chistol RO (September 2005). "[Supracondylar process and supratrochlearforamen of the humerus: a case report and a review of the literature]". Morphologie (in French). 89 (286): 121–5. doi:10.1016/S1286-0115(05)83248-5. PMID   16444940.
  5. ↑ Dellon AL, Mackinnon SE (October 1987). "Musculoaponeurotic variations along the course of the median nerve in the proximal forearm". [[J Hand Surg [Br]]]. 12 (3): 359–63. doi:10.1016/0266-7681(87)90189-6. PMID   3437205.
  6. ↑ Wertsch JJ, Melvin J (December 1982). "Median nerve anatomy and entrapment syndromes: a review". Arch Phys Med Rehabil . 63 (12): 623–7. PMID   6756339.
  7. ↑ Bilecenoglu B, Uz A, Karalezli N (April 2005). "Possible anatomic structures causing entrapment neuropathies of the median nerve: an anatomic study". Acta Orthop Belg . 71 (2): 169–76. PMID   16152850.
  8. ↑ Nigst H, Dick W (April 1979). "Syndromes of compression of the median nerve in the proximal forearm (pronator teres syndrome; anterior interosseous nerve syndrome)". Arch Orthop Trauma Surg . 93 (4): 307–12. doi:10.1007/BF00450231. PMID   464765.
  9. ↑ Kett K, Csere T, Lukács L, Szilágyi K, Illényi L (June 1979). "Histological and autoradiographic changes in locally irradiated lymph nodes (an experimental study on rabbits)". Lymphology . 12 (2): 95–100. PMID   491743.
  10. ↑ Campbell, William W.; Landau, Mark E. (2008). "Controversial Entrapment Neuropathies". Neurosurgery Clinics of North America. 19 (4): 597–608. doi:10.1016/j.nec.2008.07.001. PMID   19010284.
  11. ↑ Gunther SF, DiPasquale D, Martin R (1993). "Struthers' ligament and associated median nerve variations in a cadaveric specimen". Yale J Biol Med . 66 (3): 203–8. PMC   2588859 . PMID   8209556.
  12. ↑ ‘‘Tabulae Arteriarum’’, Plate 15, Fig 3, 1822
  13. ↑ Knox. Edinburgh Medical and Surgical Journal, 1841, p.125
  14. ↑ Gorman, Martyn. "The Zoology of Professor Struthers". Charles Darwin and Struthers' ligament. University of Aberdeen. Archived from the original on 8 September 2014. Retrieved 1 October 2012.
  15. ↑ Darwin, Charles R. (1871). The descent of man, and selection in relation to sex. John Murray. p. 28.
  16. ↑ Struthers, John (February 2007). "Historical Article: On a peculiarity of the humerus and humeral artery". Journal of Hand Surgery. 1. 32E: 54–56.

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