In the present study humerus was the largest, longest and heaviest bone of the forelimb same as reported by
Smuts and Bezuidenhout (1993) in African elephant and
Mariappa (1986) and
Lakshmishree et al., (2021) in Indian elephant. It has a proximal and a distal extremity and a shaft.
Smuts and Bezuidenhout (1987) found that the humerus was massive, particularly proximally in dromedary.
Talukdar et al., (2002) revealed that humerus of mithun was short but very strong and stout in comparison to that of the other domesticated animals.
Nurhidayat et al., (2015) recorded that the humerus of Sumatran Rhino was relatively big and short bone.
The cylindrical shaped shaft was twisted in appearance as noted by
Lakshmishree et al., (2021) in Indian elephant,
Gupta and Deshmukh (2014) in camel,
Getty (1975) in horse,
Sarma et al., (2008), Bharti et al., (2021) and
(Pawan and Suraj 1999 Rohlan et al., 2018) in Nilgai/ blue bull,
Bordoloi et al., (1991) in Indian one -horned rhinoceros,
Jangir (2010) in chinkara,
Choudhary and Singh (2016) in blackbuck,
Sarma et al., (2019) in adult Indian barking deer. However, it was spirally twisted in the African elephant
(Tefera, 2012) and flattened cranio-caudally in Indian one-horned rhinoceros
(Bordoloi et al., 1991). The shaft was consisted of four surfaces. The lateral surface was smooth. The deeper musculo-spiral groove was present in the lateral portion of the shaft of this surface same as elucidated by
Ahasan et al., (2016) in Asian elephant,
Tefera, (2012) in the African elephant and
Bordoloi et al., (1991) in Indian one-horned rhinoceros, while
Lakshmishree et al., (2021) in Indian elephant and
Muhammad and Shahid (2000) in buffalo noted a shallow musculo-spiral groove. The Musculo spiral groove was limited by the lateral epicondyloid crest at the posterior surface of the shaft. This Musculo-spiral groove was continuous with the posterior surface above in agreement with
Getty (1975) in horse.
The deltoid tuberosity was present in the proximal third of the shaft same as reported by
Bordoloi et al., (1991) in Indian one -horned rhinoceros and
Rajani et al., (2019) in Indian Muntjac. It was slightly distinct rough elevated and elongated area same as reported by
Ahasan et al., (2016) in Asian elephant however,
Mahmud and Mussa (2016) sin black Bengal goat noted in the form of a faint impression and
Onwuama et al., (2021) reviewed that in West African giraffe the deltoid tuberosity was absent.
Getty (1975) mentioned that the deltoid tuberosity was well developed in the horses.
The anterior surface was separated from lateral surface with a ridge. A well-developed deltoid ridge was present in proximal third part of the shaft of humerus. This ridge was separating the anterior surface with the lateral surface in proximal third as mentioned by
Lucy et al., (2018) in elephant. A well- developed vertical ridge was also present medial to deltoid ridge and deltoid tuberosity (Plate 1) on the anterior surface of the shaft. Similar observations were noted by
Mariappa (1986) and
Lakshmishree et al., (2021) in Indian elephant and
Choudhary and Singh (2016) in blackbuck.
A prominent structure of the crest of major tubercle was observed cranially and becomes indistinct at the middle of shaft as reported by
Smuts and Bezuidenhout (1993) in African elephant. The crest of major tubercle was in the form of rough line which was present on medial surface as reported in Indian elephant
Lakshmishree et al., (2021). However, it was well developed in Mithun
(Talukdar et al., 2002).The nutrient foramen was located distally at posterior surface as reported by
Lakshmishree et al., (2021) In Indian elephant,
Sarma and Kalita (2008) in Asian elephant and
Bordoloi et al., (1991) in Indian one-horned rhinoceros. However, it was in distal third of medial surface in horse
(Getty, 1975), whereas it was observed at distal third of lateral surface in black Bengal goat
(Siddiqui et al., 2008) and in the distal third of cranial surface in camel
(Smuts and Bezuidenhout, 1987 and
Gupta and Deshmukh, 2014).
The proximal extremity was consisted of the head, neck, two tuberosites and the intertubular groove (Plate 2) as recorded by
Lakshmishree et al., (2021) In Indian elephant,
Gupta and Deshmukh (2014) in camel,
Bordoloi et al., (1991) in Indian one-horned rhinoceros and
Getty (1975) in horse.
The head was elongated ovoid in shape. However,
Lakshmishree et al., (2021) in Indian elephant noted it as roughly spherical shape and
Gupta and Deshmukh (2014) in camel noted circular shape. The elongated flattened articular area was laterally marked by a rough faint border and forming the rounded surface of the head same as reported by
Smuts and Bezuidenhout (1993) in African elephant. It was located in the caudo-medial aspect of the proximal extremity same as in camel
Gupta and Deshmukh (2014) and was directed in cranio- caudal plane as observed by
Ahasan et al., (2016) in Asian elephant and
Smuts and Bezuidenhout (1993) in African elephant. It was about twice extensive as the glenoid cavity of scapula, but the articular area of the head was equal to the glenoid cavity.
The tuberosites present on proximal extremity were, lateral tuberosity and medial tuberosity. While
Budras et al., (2003) in bovines and
Budras et al., (2009) in equines mentioned these tuberosites as the lateral major tubercle and the medial minor tubercle. The lateral tuberosity was well developed and placed laterally to the head and extends cranially to it as mentioned by
Ahasan et al., (2016) and
Lucy et al., (2018) in Asian elephant and
Smuts and Bezuidenhout (1993) in African elephant and
Gupta and Deshmukh (2014) in camel. Lateral tuberosity was consisted of two parts,
i.
e. anterior and posterior part same as in camel
(Gupta and Deshmukh, 2014) and bovine
(Budras et al., 2003).
The medial tuberosity was very small and tuberous in shape in agreement with
Lucy et al., (2018) in elephant. However,
Budras et al., (2009) recorded that in equine the greater and lesser tubercles on the lateral and medial sides, respectively, of the proximal extremity were nearly equally well developed. In bovines these tubercles were divided into cranial and caudal parts
(Budras et al., 2003).
In between the lateral and medial tuberosites an intertubular groove (bicipital groove) (Plate 3) was present same as reported in Indian elephant by
Lakshmishree et al., (2021) and in camel by
Gupta and Deshmukh (2014).
Damian et al., (2012) concluded that in giraffe the bicipital groove was less evident.
Pawan and Suraj (1999) recorded that in Neel gai bicipital groove was shallow. The bicipital groove was present lateral to the cranial extremity of medial tuberosity and medial to the cranial part of lateral tuberosity as elucidated by
Smuts and Bezuidenhout (1993) in African elephant. However, the bicipital groove was subdivided by a prominent ridge in horse
(Konig and Liebich, 2006) and camel
(Gupta and Deshmukh, 2014).
Gupta and Deshmukh (2014) in camel noted that it was present between the lateral tuberosity and intermediate tubercle and a less developed in between intermediate tubercle and medial tuberosity.
The distal extremity was consisted of two condyles which were unequal in size and separated by a ridge as noted by
Lakshmishree et al., (2021) in Indian elephant,
Onwuama et al., (2021) in West African giraffe and
Getty (1975) in horse.
The lateral epicondyle was massive in size and was present just above the condyle which showed many minute foramina as elucidated by
Ahasan et al., (2016) in Asian elephant, In the lateral epicondyle a big tuberosity was present. The medial epicondyle was much smaller than the lateral epicondyle and lies caudally in the upper part of the condyle as described by
Smuts and Bezuidenhout (1993) in African elephant and
Smuts and Bezuidenhout (1987) in dromedary.
Just above the condyle on the anterior surface a well- developed radial fossa was present. While in one animal it was deep and elongated in shape. The radial fossa was present on the cranial aspect as observed by
Ahasan et al., (2016) in Asian elephant and
Smuts and Bezuidenhout (1993) in African elephant. Just lateral to radial fossa a somewhat smaller deep rounded fossa was present.
The olecranon fossa was formed by two epicondyles caudally. The olecranon fossa and radial fossa were not communicated with each other same as reported by
Lakshmishree et al., (2021) in Indian elephant. However,
Choudhary and Singh (2016) in black buck reported that the olecranon fossa and radial fossa communicated with each other and form supratrochlear foramen in contrast with the present finding. Both radial and olecranon fossa were deep same was recorded by
Lakshmishree et al., (2021) in Indian elephant and
Smuts and Bezuidenhout (1987) in dromedary.
There was no significant difference in between the right and left humerus of same animal same as described by
Gupta and Deshmukh (2014) in camel. In the present study weight of humerus was 17.16±0.76 kg (Table 1) nearly same weight was recorded by
Lakshmishree et al., (2021) in Indian elephant, which was 17.7 kg. In the present study the length of humerus was 84.07±1.81 cm (Table 1).
