Medial Head Of Triceps Brachii Research Articles

“Snapping triceps”: A rare and misleading condition – a clinical case report

Snapping triceps corresponds to subluxation of the medial head of the triceps brachii over the medial epicondyle during active elbow flexion. It is a rare and misleading condition that is often associated with ulnar nerve instability. The latter can result in the snapping triceps being missed. Diagnosis requires a detailed clinical examination. Surgical treatment consists of anterior translocation of the nerve with an adipose flap to stabilize it and transfer of the distal attachment of the medial head of triceps brachii.

Multiple Interneural Communications of Brachial Plexus-Anatomical Description and Clinical Significance

Brachial plexus blockade requires efficient and thorough understanding of the detailed anatomy of the plexus and the variations associated with the plexus. Anomalies associated with the branches of the plexus may complicate attempts of nerve blockade for anesthesia. The present case report presents an unusual variation of brachial plexus noticed during routine cadaveric dissection. A rare neural communication between ulnar and radial nerves was observed in the left axilla at high humeral level proximal to the entry of the radial nerve into the radial groove. The communicating ramus also gave a branch to the medial head of triceps brachii 0.3 cm distal to the origin of the communication. Further, there was also a communication between the musculocutaneous and median nerves in the distal half of the arm after the musculocutaneous nerve pierced the coracobrachialis muscle. Though the variations of the brachial plexus have been described in the literature, yet studies regarding the communication between ulnar and radial nerves are rare and the coexistence of this variation along with median and musculocutaneous nerve communication is unique. Knowledge of such rare variations and anomalies is important to minimize the possible complications of regional anesthesia and surgery. Such an unusual variation, as noted in the present study, may prove useful in nerve grafting and neurophysiological evaluation to diagnose peripheral neuropathies. Further, their knowledge is of immense importance in traumatology of the shoulder joint, radial neck dissections and management of fracture of the surgical neck of humerus. Anatomic variations of peripheral nerves are important for Orthopedic surgeons, Neurophysicians, Physiotherapists and Radiologists. The present article is a humble attempt to reinforce awareness of such neural variations among clinicians.

Bony Avulsion of the Medial Head of Triceps Brachii

We describe a 69-year-old patient who presented with an isolated avulsion fracture of the medial head of triceps brachii after a fall onto her elbow. As far as we are aware, this pattern of injury has not been previously described in the literature. Our patient had no functional deficit and was managed conservatively. She was referred for physiotherapy, and discharged once her pain subsequently subsided. Although the literature favours surgical management of similar injuries, we feel that our case shows that good results may still be achieved from conservative management.

Tardy ulnar nerve palsy caused by cubitus varus deformity

Clinical features and X-rays of thirty-four cases with cubitus varus deformity were analysed in order to explain the occurrence of tardy ulnar nerve palsy caused by cubitus varus deformity. Cubitus varus cases with tardy ulnar nerve palsy, compared to cases without it, were older at the first visit to the clinic for cubitus varus deformity. There were no other differences between the two groups in clinical features. Computed tomography showed that the olecranon moved to the ulnar side against the olecranon fossa. Operative findings showed that the medial head of triceps brachii shifted medially and covered the ulnar nerve. Both from computed tomography and operative findings we conjectured the possibility that tardy ulnar nerve palsy was caused because the ulnar nerve was compressed by the forward medial movement of the medial head of the triceps brachii caused by cubitus varus deformity.

Tardy Ulnar Nerve Palsy Caused by Cubitus Varus Deformity

Clinical features and X-rays of thirty-four cases with cubitus varus deformity were analysed in order to explain the occurrence of tardy ulnar nerve palsy caused by cubitus varus deformity. Cubitus varus cases with tardy ulnar nerve palsy, compared to cases without it, were older at the first visit to the clinic for cubitus varus deformity. There were no other differences between the two groups in clinical features. Computed tomography showed that the olecranon moved to the ulnar side against the olecranon fossa. Operative findings showed that the medial head of triceps brachii shifted medially and covered the ulnar nerve. Both from computed tomography and operative findings we conjectured the possibility that tardy ulnar nerve palsy was caused because the ulnar nerve was compressed by the forward medial movement of the medial head of the triceps brachii caused by cubitus varus deformity.

Dynamics of neck-to-forelimb reflexes in the decerebrate cat.

We have studied the neck-to-forelimb reflex evoked by head rotation around the longitudinal axis (roll) in the long and medial heads of triceps brachii of decerebrate, acutely labyrinthectomized cats. Reflexes were measured by recording mass electromyogram (EMG). As expected from the work of others, they were reciprocal in the two limbs, with excitation in the limb toward which the chin rotates. The reflex was sufficiently linear for a sinusoidal analysis. Although there was sometimes adaptation at stimulus frequencies of 0.1 Hz and below, response phase at these frequencies was usually in phase with position, and gain was flat. At higher frequencies there was some sensitivity to the velocity of the stimulus: gain increased with a slope of 10 dB/decade and phase advanced in some cats but not in others. Gain at low frequencies of head rotation, expressed as percent modulation of EMG, was typically 1%/deg or less. Reflexes evoked by head rotation in triceps and in the neck extensor splenius capitis have different dynamics. It remains to be determined whether this difference is due to activation of different receptors. We compared the dynamics of roll reflexes evoked by stimulation of neck receptors with those of vestibular reflexes evoked by tilt of the whole animal (23). Taking into account dynamics and gain, the two reflexes should cancel at low frequencies, as predicted by others. Above 0.2 Hz, cancellation becomes less effective.

Effect of training on skeletal muscle injury from downhill running in rats.

Experiments were conducted to test the hypothesis that injury to skeletal muscle in rats resulting from prolonged downhill running is prevented to a greater extent by prior downhill training than by either uphill or level training. Changes in plasma creatine phosphokinase (CPK) activity and glucose-6-phosphate dehydrogenase (G-6-PDase) activity in the soleus (S), vastus intermedius (VI), and medial head of triceps brachii (TM) muscles were evaluated as markers of muscle injury 48 h after 90 min of intermittent downhill running (16 m . min -1). Prior to this acute downhill run, groups of rats were trained by either downhill (-16 degrees), level (0 degrees), or uphill (+16 degrees) running (16 m . min -1) for 30 min/day. Training duration was either 5 days or 1 day. A training effect (i.e., reduced muscle injury) was indicated if muscle G-6-PDase or plasma CPK activity in a trained group following the 90-min downhill run was not different from that of nonexercised control animals and/or if it was lower than that of nontrained runners. A significant training effect was achieved in all three muscles with 5 days of either downhill or level training, but only in S after 5 days of uphill training. Elevation of plasma CPK activity was prevented by 5 days of training on all three inclines.(ABSTRACT TRUNCATED AT 250 WORDS)

EFFECT OF TRAINING ON SKELETAL MUSCLE INJURY FROM DOWNHILL RUNNING IN RATS

Experiments were conducted to test the hypothesis that injury to skeletal muscle in rats resulting from prolonged downhill running is prevented to a greater extent by prior downhill training than by either uphill or level training. Changes in plasma creatine phosphokinase (CPK) activity and glucose-6-phosphate dehydrogenase (G-6-PDase) activity in the soleus (S), vastus intermedius (VI), and medial head of triceps brachii (TM) muscles were evaluated as markers of muscle injury 48 h after 90 min of intermittent downhill running (16 m . min -1). Prior to this acute downhill run, groups of rats were trained by either downhill (-16 degrees), level (0 degrees), or uphill (+16 degrees) running (16 m . min -1) for 30 min/day. Training duration was either 5 days or 1 day. A training effect (i.e., reduced muscle injury) was indicated if muscle G-6-PDase or plasma CPK activity in a trained group following the 90-min downhill run was not different from that of nonexercised control animals and/or if it was lower than that of nontrained runners. A significant training effect was achieved in all three muscles with 5 days of either downhill or level training, but only in S after 5 days of uphill training. Elevation of plasma CPK activity was prevented by 5 days of training on all three inclines.(ABSTRACT TRUNCATED AT 250 WORDS)

Observations on normal skeletal muscle of mature dogs: a cytochemical, histochemical, and morphometric study.

Cytochemical, histochemical, and morphometric features of skeletal muscle were evaluated in 140 specimens from five appendicular muscles of 28 dogs which were free of neuromuscular disease. Dogs ranged from six months to 15 years of age. Evidence of degeneration and regeneration, cell reactions and architectural change was found but with an incidence of less than 1% of the total myofiber population in any muscle. The number of fibers with internal nuclei never exceeded 1%. The only changes that appeared to be age-related were fiber size variation associated with the presence of small angular type IIA fibers in muscles of dogs seven years of age and older. Percentages of type I, type IIA, and type IIC fibers remained relatively constant in the various muscles in the age range examined. Type I fibers predominated in medial head of triceps brachii and superficial digital flexor muscles, whereas type IIA fibers were more numerous in biceps femoris and long head of triceps brachii muscles. An approximately equal ratio was found in gastrocranius muscles. In any given muscle, type IIC fibers represented less than 2% of the fibers. Statistically significant differences were found in values for fiber size between groups of dogs weighing more than (mean diameter range = 40 to 50 microns) and less than (mean diameter range = 30 to 40 microns) 15 kilograms.

An Electromyographic Study of Shoulder Muscles during Bilateral Sanding: A Pilot Study

Bilateral sanding is used by occupational therapists as a therapeutic exercise technique, however, to-date no data have been available identifying the musculature involved in the activity nor the extent of that involvement. The dual purpose of this pilot study was to; (a) delineate the activity of selected shoulder muscles during bilateral sanding, and (b) determine whether the method used would be feasible in the analysis of other therapeutic activities. For this investigation, a quadriplegic individual was matched for height and weight with a normal subject and both were tested under several controlled conditions of bilateral sanding. Right shoulder complex musculature was electromyographically (EMG) investigated and the muscles studied were: pectoralis major, biceps brachii, the three heads of deltoid, and the lateral and medial heads of triceps brachii. EMG data for the two subjects were normalized and represented as percentages of the maximal voluntary contractions (MVC) relative for each muscle. This technique allowed intra- and inter-subject comparisons of muscle activity. Recognizing the limitations of the study with the major one being the small number of subjects, useful information was obtained from the results. The quadriplegic individual appeared to be more inefficient in his muscle usage than the normal subject. This may be related to trunk instability in the quadriplegic subject. All three heads of the deltoid appeared to be the most highly used of monitored muscles in both the normal and the quadriplegic with triceps being only moderately active in the quadriplegic individual. Spring resisted bilateral sanding produced the most EMG activity in all muscles studied in both subjects. Further investigations employing a larger number of subjects may further elucidate EMG activity during bilateral sanding. It would appear that EMG investigations of therapeutic activities offer an informative method of physical activity analysis.

Lipoprotein lipase and uptake of chylomicron triglyceride by skeletal muscle of rats.

Uptake of chylomicron triglyceride and lipoprotein lipase was studied in red and white skeletal muscles, heart, and adipose tissue of rats. Retention of triglyceride fatty acids 10 min after injection was 1.6%/g in heart and adipose tissue, 0.2-0.4%/g in red (soleus and diaphragm) muscles, and 0.1%/g in white (psoas minor) muscles of fed rats. Fasting (24 h) increased retention two- to fourfold in red skeletal muscles and heart, had no effect in white muscles, and decreased retention greater than 75% in adipose tissue. Lipoprotein lipase activity in fed rats was lowest in white muscles and in certain red (posterior belly of digastric and medial head of triceps brachii) musclws, intermediate in soleus and diaphragm muscles and adipose tissue, and highest in heart. Fasting doubled lipoprotein lipase activity in all red skeletal muscles and heart, had no effect in white muscles, and decreased activity 60% in adipose tissue. The findings indicate that triglyceride uptake is related to lipoprotein lipase activity in skeletal muscle and the changes in enzyme activity during fasting divert blood triglyceride to red skeletal muscles.