The Suspensory Apparatus and Digital Flexor Muscles of the Llama (Lama glama) 2: The Pelvic Limb

Abstract

This paper provides data (text and illustrations) about the digital flexor muscles of the pelvic limb and the / metatarsophalangeal joint, evaluating the suspensory (support) apparatus and weight bearing structures. Similar to the above mentioned paper, a literature search provided incomplete information about these anatomical structures. As in the thoracic limb, unique anatomically variations exist in the pelvic limb of the llama. The caudal tibial muscle is fused with the lateral head of the deep digital flexor muscle (DDF), and the soleus muscle is missing. A symmetrical unexpected lumbricalis pedis muscle was found; the tendons are fusing with the axial branches of the lateral tendon of the long digital extensor muscle. A quadratus plantae muscle, also unexpected is present on the medial aspect of the tarsal region. The superficial digital flexor muscle (SDF) resembles that of the domestic ruminants. The metacarpo/ metatarsophalangeal joints, referred to as the fetlock joints (FJ) are very different from those of the domestic ruminants. Particular structures were found and they will be described and illustrated in the text. The anatomy of the suspensory (support) apparatus in the pelvic limb is evaluated in this paper.

Comparative anatomic and morphometric examination of the interosseous muscle, sesamoid ligaments and flexor tendons of the fetlock in South American camelids

“…The definition as the insertion of the palmar/plantar annular ligament and the proximal digital annular ligament consistent with Constantinescu et al. (2008a) seems preferable.…”

“…In lamas, the lumbricalis muscle has been described to come in a single or double form (Constantinescu et al., 2008a,b; Reed, 2008; Lesbre, 1903, cited by Constantinescu et al., 2008b).…”

“…While there are numerous clinical studies on distal limb disease in South American Camelids (SACs) (Cashman et al., 1999; Reed, 2008; Hunter & Semevolos, 2013), there is only limited information on the anatomy of the distal limb. The literature on the anatomy of the metacarpophalangeal/metatarsophalangeal region (from hereon referred to as ‘fetlock region’) of the alpaca (Dos Santos Romero, 2014), lama (Galotta & Arzone, 2003; Reed, 2008; Constantinescu, Reed, & Constantinescu, 2008a,b) and guanaco (König et al., 2003) is contradicting and details vary between authors. These results might suggest anatomic differences between the species of SACs or might as well be based on different interpretations of the complex structures of the region by different authors.…”

“…Note: In the pairwise tests for alpaca in reference to vicuna, the 95% confidence level of the Tukey test does not include a difference of zero and is therefore significant. Abbreviations: A, alpaca; V, vicuna; L, lama; G, guanaco annular ligament consistent withConstantinescu et al (2008a) seems preferable.…”

Macroscopic and histological investigation of guanaco footpads (Lama guanicoe, Müller 1776)

“…Tendons and ligaments are arranged adequately to maintain the position of the digits. They result in the hyperextended stabilization of the joint between the proximal and middle phalanges, the middle and distal phalanges being horizontal to the ground (Clayton and Flood, ; König et al, ; Constantinescu et al, ). Both distal phalanges of a digit and their joints rest on a common soft footpad ( torus digitalis ) that ensures contact to the ground by flexible adjustment of its surface to irregularities in the area of support (König et al, ).…”