Four-headed biceps and triceps brachii muscles, with neurovascular variation.

Anatomical variations of the biceps brachii and triceps brachii have been described by various authors, but the occurrence of four-headed biceps brachii and triceps brachii in an ipsilateral arm is rare and has not been reported before in the literature. During routine cadaveric dissection in the department of anatomy, Kasturba Medical College, Mangalore, India, various unusual variants were noted in the left arm of a cadaver of a 67-year-old man. The variants include a four-headed biceps, a four-headed triceps, communication between the musculocutaneous and median nerves, and a high origin of deep brachial artery from the axillary artery. The occurrence of these anomalies and the clinical and morphological significance are discussed.

The mendosal suture of the occipital bone: occurrence in Indian population, embryology and clinical significance.

The occipital bone is ontogenetically and functionally unique when compared to the other bones of the skull in humans and other mammalian cousins. The occipital bone develops from six ossification centers; any defect in the ossification process will give rise to mendosal suture (accessory suture) and conditions like posterior plagiocephaly. There is a paucity of literature regarding the mendosal suture and further more, its report in Indian population is not known. The present study was conducted to find out the occurrence of mendosal suture in the Indian dry skulls. Fifteen specimens (3%) were found to have these sutures out of five hundred (500) skulls examined. Nine (3.1%) samples are of male skulls out of two hundred ninety (290) and six (2.85%) samples are that of female skulls out of two hundred ten (210). The mendosal suture ran close to the superior nuchal line in all specimens and traveled medially from the lambdoidal suture. The length of the sutures ranged from 0.8 cm to 2.6 cm (1.88 cm) on the right side and 1.4 cm to 2.9 cm (1.94 cm) on the left side respectively in male skulls; and 0.7 cm to 2.8 cm (1.55 cm) on the right side and 1 cm to 2.4 cm (1.42 cm) on the left side, respectively, in female skulls. The origin of mendosal suture from the lambdoidal suture was 5.7 cm to -6.3 cm (5.98 cm) from the tip of the mastoid process on the right side and 5.6 to -6.3 cm (6 cm) on the left side, respectively, in male skulls; and 5.4 cm to -5.8 cm (5.58 cm) on the right side and 5.4 cm to -5.6 cm on the left side respectively in female skulls. The occurrence and clinical significance of the present study is discussed.

An additional radial wrist extensor and its clinical significance.

The knowledge of anatomical variations in the antebrachial and dorsal regions of the arm and hand are useful in hand surgery. The extensor carpi radialis intermedius and extensor carpi radialis accessorius are two classic variants described for the radial wrist extensors, in the antebrachial region. We report an additional extensor carpi radialis muscle taking origin from the common extensor origin, between the extensor carpi radialis longus and extensor digitorum communis. The tendon of the variant muscle divides below the abductor pollicis longus and becomes attached to the base of the second and third metacarpal bone. Due to its considerable size and independent origin from the lateral epicondyle, we suggest the present variation should be named extensor carpi radialis tertius. The clinical significance of the present variation is discussed.

An unusually lengthy styloid process.

The close proximity of the styloid process to many of the vital neurovascular structures in the neck makes it clinically significant. Abnormal elongation of the styloid process may cause compression on a number of vital vessels and nerves related to it, producing inflammatory changes that include continuous chronic pain in the pharyngeal region, radiating otalgia, phantom foreign body sensation (globus hystericus), pain in the pharyngeal region, and dysphagia. The normal length of the styloid process is usually 2.0-2.5 cm long. We report a dry human skull that showed bilateral styloid processes measuring 6.0 cm on the right side and 5.9 cm on the left side. The variation in dimension of the process and its clinical implication are discussed.